OMAPDSS: DISPC: Handle synclost errors in OMAP3

Started by Chandrabhanu Mahapatra on Mar 21, 2012 · 9 messages from 2 authors · Last reply Mar 27, 2012

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Message details and related content
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrj채l채 [off-list ref] in Linux OMAP kernel. Ville
Syrj채l채 [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 5a1963e..d8a1672 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -1622,6 +1622,57 @@ static void calc_dma_rotation_offset(u8 rotation, bool mirror,
 	}
 }
 
+static int check_horiz_timing(enum omap_channel channel, u16 pos_x,
+		u16 width, u16 height, u16 out_width, u16 out_height)
+{
+	int DS = DIV_ROUND_UP(height, out_height);
+	struct omap_dss_device *dssdev = dispc_mgr_get_device(channel);
+	struct omap_video_timings t = dssdev->panel.timings;
+	unsigned long nonactive, lclk, pclk;
+	static const u8 limits[3] = { 8, 10, 20 };
+	u64 val, blank;
+	int i;
+
+	nonactive = t.x_res + t.hfp + t.hsw + t.hbp - out_width;
+	pclk = dispc_mgr_pclk_rate(channel);
+	lclk = dispc_mgr_lclk_rate(channel);
+
+	i = 0;
+	if (out_height < height)
+		i++;
+	if (out_width < width)
+		i++;
+	blank = div_u64((u64)(t.hbp + t.hsw + t.hfp) * lclk, pclk);
+	DSSDBG("blanking period + ppl = %llu (limit = %u)\n", blank, limits[i]);
+	if (blank <= limits[i])
+		return -EINVAL;
+
+	/*
+	 * Pixel data should be prepared before visible display point starts.
+	 * So, atleast DS-2 lines must have already been fetched by DISPC
+	 * during nonactive - pos_x period.
+	 */
+	val = div_u64((u64)(nonactive - pos_x) * lclk, pclk);
+	DSSDBG("(nonactive - pos_x) * pcd = %llu,"
+		" max(0, DS - 2) * width = %d\n",
+		val, max(0, DS - 2) * width);
+	if (val < max(0, DS - 2) * width)
+		return -EINVAL;
+
+	/*
+	 * All lines need to be refilled during the nonactive period of which
+	 * only one line can be loaded during the active period. So, atleast
+	 * DS - 1 lines should be loaded during nonactive period.
+	 */
+	val =  div_u64((u64)nonactive * lclk, pclk);
+	DSSDBG("nonactive * pcd  = %llu, max(0, DS - 1) * width = %d\n",
+		val, max(0, DS - 1) * width);
+	if (val < max(0, DS - 1) * width)
+		return -EINVAL;
+
+	return 0;
+}
+
 static unsigned long calc_fclk_five_taps(enum omap_channel channel, u16 width,
 		u16 height, u16 out_width, u16 out_height,
 		enum omap_color_mode color_mode)
@@ -1702,7 +1753,7 @@ static int dispc_ovl_calc_scaling(enum omap_plane plane,
 		enum omap_channel channel, u16 width, u16 height,
 		u16 out_width, u16 out_height,
 		enum omap_color_mode color_mode, bool *five_taps,
-		int *x_predecim, int *y_predecim)
+		int *x_predecim, int *y_predecim, u16 pos_x)
 {
 	struct omap_overlay *ovl = omap_dss_get_overlay(plane);
 	const int maxdownscale = dss_feat_get_param_max(FEAT_PARAM_DOWNSCALE);
@@ -1778,6 +1829,9 @@ static int dispc_ovl_calc_scaling(enum omap_plane plane,
 			fclk = calc_fclk_five_taps(channel, in_width, in_height,
 				out_width, out_height, color_mode);
 
+			error = check_horiz_timing(channel, pos_x, in_width,
+				in_height, out_width, out_height);
+
 			if (in_width > maxsinglelinewidth)
 				if (in_height > out_height &&
 					in_height < out_height * 2)
@@ -1785,7 +1839,7 @@ static int dispc_ovl_calc_scaling(enum omap_plane plane,
 			if (!*five_taps)
 				fclk = calc_fclk(channel, in_width, in_height,
 					out_width, out_height);
-			error = (in_width > maxsinglelinewidth * 2 ||
+			error = (error || in_width > maxsinglelinewidth * 2 ||
 				(in_width > maxsinglelinewidth && *five_taps) ||
 				!fclk || fclk > dispc_fclk_rate());
 			if (error) {
@@ -1801,6 +1855,12 @@ static int dispc_ovl_calc_scaling(enum omap_plane plane,
 		} while (decim_x <= *x_predecim && decim_y <= *y_predecim
 			&& error);
 
+		if (check_horiz_timing(channel, pos_x, width, height,
+			out_width, out_height)){
+				DSSERR("horizontal timing too tight\n");
+				return -EINVAL;
+		}
+
 		if (in_width > (maxsinglelinewidth * 2)) {
 			DSSERR("Cannot setup scaling");
 			DSSERR("width exceeds maximum width possible");
@@ -1901,7 +1961,7 @@ int dispc_ovl_setup(enum omap_plane plane, struct omap_overlay_info *oi,
 
 	r = dispc_ovl_calc_scaling(plane, channel, in_width, in_height,
 			out_width, out_height, oi->color_mode, &five_taps,
-			&x_predecim, &y_predecim);
+			&x_predecim, &y_predecim, oi->pos_x);
 	if (r)
 		return r;
 
@@ -2472,32 +2532,19 @@ unsigned long dispc_fclk_rate(void)
 
 unsigned long dispc_mgr_lclk_rate(enum omap_channel channel)
 {
-	struct platform_device *dsidev;
-	int lcd;
-	unsigned long r;
-	u32 l;
+	unsigned long r = dispc_fclk_rate();
 
-	l = dispc_read_reg(DISPC_DIVISORo(channel));
+	if (dispc_mgr_is_lcd(channel)) {
+		u32 l;
+		int lcd;
 
-	lcd = FLD_GET(l, 23, 16);
+		l = dispc_read_reg(DISPC_DIVISORo(channel));
+		lcd = FLD_GET(l, 23, 16);
 
-	switch (dss_get_lcd_clk_source(channel)) {
-	case OMAP_DSS_CLK_SRC_FCK:
-		r = clk_get_rate(dispc.dss_clk);
-		break;
-	case OMAP_DSS_CLK_SRC_DSI_PLL_HSDIV_DISPC:
-		dsidev = dsi_get_dsidev_from_id(0);
-		r = dsi_get_pll_hsdiv_dispc_rate(dsidev);
-		break;
-	case OMAP_DSS_CLK_SRC_DSI2_PLL_HSDIV_DISPC:
-		dsidev = dsi_get_dsidev_from_id(1);
-		r = dsi_get_pll_hsdiv_dispc_rate(dsidev);
-		break;
-	default:
-		BUG();
+		return r / lcd;
+	} else {
+		return r;
 	}
-
-	return r / lcd;
 }
 
 unsigned long dispc_mgr_pclk_rate(enum omap_channel channel)
-- 
1.7.1

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Message details and related content
Hi,

On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrjälä [off-list ref] in Linux OMAP kernel. Ville
Syrjälä [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
The patch seems to be using dos line endings... Where did they come
from? The two others are fine. I think git am removed the dos line
endings, so it's fine.

 Tomi


ERROR: DOS line endings
#72: FILE: drivers/video/omap2/dss/dispc.c:1625:
+static int check_horiz_timing(enum omap_channel channel, u16 pos_x,^M$

ERROR: DOS line endings
#73: FILE: drivers/video/omap2/dss/dispc.c:1626:
+^I^Iu16 width, u16 height, u16 out_width, u16 out_height)^M$

ERROR: DOS line endings
#74: FILE: drivers/video/omap2/dss/dispc.c:1627:
+{^M$

ERROR: DOS line endings
#75: FILE: drivers/video/omap2/dss/dispc.c:1628:
+^Iint DS = DIV_ROUND_UP(height, out_height);^M$

ERROR: DOS line endings
#76: FILE: drivers/video/omap2/dss/dispc.c:1629:
+^Istruct omap_dss_device *dssdev = dispc_mgr_get_device(channel);^M$

ERROR: DOS line endings
#77: FILE: drivers/video/omap2/dss/dispc.c:1630:
+^Istruct omap_video_timings t = dssdev->panel.timings;^M$

ERROR: DOS line endings
#78: FILE: drivers/video/omap2/dss/dispc.c:1631:
+^Iunsigned long nonactive, lclk, pclk;^M$

ERROR: DOS line endings
#79: FILE: drivers/video/omap2/dss/dispc.c:1632:
+^Istatic const u8 limits[3] = { 8, 10, 20 };^M$

276 more lines

Message details and related content
On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
quoted hunk
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrjälä [off-list ref] in Linux OMAP kernel. Ville
Syrjälä [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 5a1963e..d8a1672 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -1622,6 +1622,57 @@ static void calc_dma_rotation_offset(u8 rotation, bool mirror,
 	}
 }
 
+static int check_horiz_timing(enum omap_channel channel, u16 pos_x,
+		u16 width, u16 height, u16 out_width, u16 out_height)
I think the function could be named check_horiz_timing_omap3 or
something. It's kinda hard to realize that this is an omap3 work-around.
Perhaps a short comment above the function would be in order.
quoted hunk
+{
+	int DS = DIV_ROUND_UP(height, out_height);
+	struct omap_dss_device *dssdev = dispc_mgr_get_device(channel);
+	struct omap_video_timings t = dssdev->panel.timings;
+	unsigned long nonactive, lclk, pclk;
+	static const u8 limits[3] = { 8, 10, 20 };
+	u64 val, blank;
+	int i;
+
+	nonactive = t.x_res + t.hfp + t.hsw + t.hbp - out_width;
+	pclk = dispc_mgr_pclk_rate(channel);
+	lclk = dispc_mgr_lclk_rate(channel);
+
+	i = 0;
+	if (out_height < height)
+		i++;
+	if (out_width < width)
+		i++;
+	blank = div_u64((u64)(t.hbp + t.hsw + t.hfp) * lclk, pclk);
+	DSSDBG("blanking period + ppl = %llu (limit = %u)\n", blank, limits[i]);
+	if (blank <= limits[i])
+		return -EINVAL;
+
+	/*
+	 * Pixel data should be prepared before visible display point starts.
+	 * So, atleast DS-2 lines must have already been fetched by DISPC
+	 * during nonactive - pos_x period.
+	 */
+	val = div_u64((u64)(nonactive - pos_x) * lclk, pclk);
+	DSSDBG("(nonactive - pos_x) * pcd = %llu,"
+		" max(0, DS - 2) * width = %d\n",
+		val, max(0, DS - 2) * width);
+	if (val < max(0, DS - 2) * width)
+		return -EINVAL;
+
+	/*
+	 * All lines need to be refilled during the nonactive period of which
+	 * only one line can be loaded during the active period. So, atleast
+	 * DS - 1 lines should be loaded during nonactive period.
+	 */

102 more quoted lines

I don't the change to dispc_mgr_lclk_rate has anything to do with this
patch (fixing omap3 sync lost error). Shouldn't it be a separate fix?

 Tomi
Message details and related content
On Tue, 2012-03-27 at 16:31 +0530, Mahapatra, Chandrabhanu wrote:
On Tue, Mar 27, 2012 at 4:13 PM, Tomi Valkeinen [off-list ref] wrote:
quoted
Hi,

On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
quoted
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrjälä [off-list ref] in Linux OMAP kernel. Ville
Syrjälä [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
The patch seems to be using dos line endings... Where did they come
from? The two others are fine. I think git am removed the dos line
endings, so it's fine.
How did you find these errors? scripts/checkpatch.pl still returns me nothing.
Well I just saved the email and ran checkpatch. Could be a problem in
gmail or my end too, but I've never seen it happen before.

 Tomi
Message details and related content
On Tue, Mar 27, 2012 at 4:13 PM, Tomi Valkeinen [off-list ref] wrote:
Hi,

On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
quoted
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrjälä [off-list ref] in Linux OMAP kernel. Ville
Syrjälä [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
The patch seems to be using dos line endings... Where did they come
from? The two others are fine. I think git am removed the dos line
endings, so it's fine.
How did you find these errors? scripts/checkpatch.pl still returns me nothing.
 Tomi


ERROR: DOS line endings
#72: FILE: drivers/video/omap2/dss/dispc.c:1625:
+static int check_horiz_timing(enum omap_channel channel, u16 pos_x,^M$

ERROR: DOS line endings
#73: FILE: drivers/video/omap2/dss/dispc.c:1626:
+^I^Iu16 width, u16 height, u16 out_width, u16 out_height)^M$

ERROR: DOS line endings
#74: FILE: drivers/video/omap2/dss/dispc.c:1627:
+{^M$

ERROR: DOS line endings
#75: FILE: drivers/video/omap2/dss/dispc.c:1628:
+^Iint DS = DIV_ROUND_UP(height, out_height);^M$

ERROR: DOS line endings
#76: FILE: drivers/video/omap2/dss/dispc.c:1629:
+^Istruct omap_dss_device *dssdev = dispc_mgr_get_device(channel);^M$

ERROR: DOS line endings
#77: FILE: drivers/video/omap2/dss/dispc.c:1630:
+^Istruct omap_video_timings t = dssdev->panel.timings;^M$

ERROR: DOS line endings
#78: FILE: drivers/video/omap2/dss/dispc.c:1631:
+^Iunsigned long nonactive, lclk, pclk;^M$

ERROR: DOS line endings
#79: FILE: drivers/video/omap2/dss/dispc.c:1632:
+^Istatic const u8 limits[3] = { 8, 10, 20 };^M$

ERROR: DOS line endings
#80: FILE: drivers/video/omap2/dss/dispc.c:1633:
+^Iu64 val, blank;^M$

ERROR: DOS line endings

271 more quoted lines



-- 
Chandrabhanu Mahapatra
Texas Instruments India Pvt. Ltd.
Message details and related content
On Tue, 2012-03-27 at 16:37 +0530, Mahapatra, Chandrabhanu wrote:
On Tue, Mar 27, 2012 at 4:27 PM, Tomi Valkeinen [off-list ref] wrote:
quoted
On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
quoted
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrjälä [off-list ref] in Linux OMAP kernel. Ville
Syrjälä [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 5a1963e..d8a1672 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -1622,6 +1622,57 @@ static void calc_dma_rotation_offset(u8 rotation, bool mirror,
      }
 }

+static int check_horiz_timing(enum omap_channel channel, u16 pos_x,
+             u16 width, u16 height, u16 out_width, u16 out_height)
I think the function could be named check_horiz_timing_omap3 or
something. It's kinda hard to realize that this is an omap3 work-around.
Perhaps a short comment above the function would be in order.
Yes, you are right! Do you mean to include some comments within the
code definition itself? The patch description includes all that this
function does.
I mean just a short comment above the function that mentions that this
function is used to avoid the synclosts on omap3, because yadda yadda,
so that the reader will immediately realize that this is doing some
special handling. 
quoted
I don't the change to dispc_mgr_lclk_rate has anything to do with this
patch (fixing omap3 sync lost error). Shouldn't it be a separate fix?

 Tomi
I am thinking to to move this fix to the third patch in the series
"OMAPDSS: DISPC: Correct DISPC functional clock usage" and make it
separate patch from the series and if possible move it ahead of the
predecimation patch series. What do you say?
This patch is using dispc_mgr_lclk_rate. Does it depend on the change?
If so, it needs to be fixed before this patch. But yes, separating it
sounds fine. 

 Tomi
Message details and related content
On Tue, Mar 27, 2012 at 4:27 PM, Tomi Valkeinen [off-list ref] wrote:
On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
quoted
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrjälä [off-list ref] in Linux OMAP kernel. Ville
Syrjälä [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 5a1963e..d8a1672 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -1622,6 +1622,57 @@ static void calc_dma_rotation_offset(u8 rotation, bool mirror,
      }
 }

+static int check_horiz_timing(enum omap_channel channel, u16 pos_x,
+             u16 width, u16 height, u16 out_width, u16 out_height)
I think the function could be named check_horiz_timing_omap3 or
something. It's kinda hard to realize that this is an omap3 work-around.
Perhaps a short comment above the function would be in order.
Yes, you are right! Do you mean to include some comments within the
code definition itself? The patch description includes all that this
function does.
quoted
+{
+     int DS = DIV_ROUND_UP(height, out_height);
+     struct omap_dss_device *dssdev = dispc_mgr_get_device(channel);
+     struct omap_video_timings t = dssdev->panel.timings;
+     unsigned long nonactive, lclk, pclk;
+     static const u8 limits[3] = { 8, 10, 20 };
+     u64 val, blank;
+     int i;
+
+     nonactive = t.x_res + t.hfp + t.hsw + t.hbp - out_width;
+     pclk = dispc_mgr_pclk_rate(channel);
+     lclk = dispc_mgr_lclk_rate(channel);
+
+     i = 0;
+     if (out_height < height)
+             i++;
+     if (out_width < width)
+             i++;
+     blank = div_u64((u64)(t.hbp + t.hsw + t.hfp) * lclk, pclk);
+     DSSDBG("blanking period + ppl = %llu (limit = %u)\n", blank, limits[i]);
+     if (blank <= limits[i])
+             return -EINVAL;
+
+     /*
+      * Pixel data should be prepared before visible display point starts.
+      * So, atleast DS-2 lines must have already been fetched by DISPC
+      * during nonactive - pos_x period.
+      */
+     val = div_u64((u64)(nonactive - pos_x) * lclk, pclk);
+     DSSDBG("(nonactive - pos_x) * pcd = %llu,"
+             " max(0, DS - 2) * width = %d\n",
+             val, max(0, DS - 2) * width);
+     if (val < max(0, DS - 2) * width)
+             return -EINVAL;
+
+     /*
+      * All lines need to be refilled during the nonactive period of which
+      * only one line can be loaded during the active period. So, atleast
+      * DS - 1 lines should be loaded during nonactive period.
+      */

108 more quoted lines

I am thinking to to move this fix to the third patch in the series
"OMAPDSS: DISPC: Correct DISPC functional clock usage" and make it
separate patch from the series and if possible move it ahead of the
predecimation patch series. What do you say?


-- 
Chandrabhanu Mahapatra
Texas Instruments India Pvt. Ltd.
Message details and related content
On Tue, Mar 27, 2012 at 4:40 PM, Tomi Valkeinen [off-list ref] wrote:
On Tue, 2012-03-27 at 16:31 +0530, Mahapatra, Chandrabhanu wrote:
quoted
On Tue, Mar 27, 2012 at 4:13 PM, Tomi Valkeinen [off-list ref] wrote:
quoted
Hi,

On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
quoted
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrjälä [off-list ref] in Linux OMAP kernel. Ville
Syrjälä [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
The patch seems to be using dos line endings... Where did they come
from? The two others are fine. I think git am removed the dos line
endings, so it's fine.
How did you find these errors? scripts/checkpatch.pl still returns me nothing.
Well I just saved the email and ran checkpatch. Could be a problem in
gmail or my end too, but I've never seen it happen before.

 Tomi
Save it as text file and then run checkpatch it wont give any errors.
By default it tries to save it as a eml file. Just check it.


-- 
Chandrabhanu Mahapatra
Texas Instruments India Pvt. Ltd.
Message details and related content
On Tue, Mar 27, 2012 at 4:47 PM, Tomi Valkeinen [off-list ref] wrote:
On Tue, 2012-03-27 at 16:37 +0530, Mahapatra, Chandrabhanu wrote:
quoted
On Tue, Mar 27, 2012 at 4:27 PM, Tomi Valkeinen [off-list ref] wrote:
quoted
On Wed, 2012-03-21 at 15:21 +0530, Chandrabhanu Mahapatra wrote:
quoted
In OMAP3 DISPC video overlays suffer from some undocumented horizontal position
and timing related limitations leading to SYNCLOST errors. Whenever the image
window is moved towards the right of the screen SYNCLOST errors become
frequent. Checks have been implemented to see that DISPC driver rejects
configuration exceeding above limitations.

This code was successfully tested on OMAP3. This code is written based on code
written by Ville Syrjälä [off-list ref] in Linux OMAP kernel. Ville
Syrjälä [off-list ref] had added checks for video overlay horizontal
timing and DISPC horizontal blanking length limitations.

Signed-off-by: Chandrabhanu Mahapatra <redacted>
---
 drivers/video/omap2/dss/dispc.c |   97 +++++++++++++++++++++++++++++----------
 1 files changed, 72 insertions(+), 25 deletions(-)
diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index 5a1963e..d8a1672 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -1622,6 +1622,57 @@ static void calc_dma_rotation_offset(u8 rotation, bool mirror,
      }
 }

+static int check_horiz_timing(enum omap_channel channel, u16 pos_x,
+             u16 width, u16 height, u16 out_width, u16 out_height)
I think the function could be named check_horiz_timing_omap3 or
something. It's kinda hard to realize that this is an omap3 work-around.
Perhaps a short comment above the function would be in order.
Yes, you are right! Do you mean to include some comments within the
code definition itself? The patch description includes all that this
function does.
I mean just a short comment above the function that mentions that this

4 more quoted lines

Ok.
quoted
quoted
I don't the change to dispc_mgr_lclk_rate has anything to do with this
patch (fixing omap3 sync lost error). Shouldn't it be a separate fix?

 Tomi
I am thinking to to move this fix to the third patch in the series
"OMAPDSS: DISPC: Correct DISPC functional clock usage" and make it
separate patch from the series and if possible move it ahead of the
predecimation patch series. What do you say?
This patch is using dispc_mgr_lclk_rate. Does it depend on the change?
If so, it needs to be fixed before this patch. But yes, separating it
sounds fine.

 Tomi
To a certain extent it does. Moving it to the third patch will
introduce certain code changes as
if (dispc_mgr_is_lcd(channel)) while initialising dispc_core_clk.
Anyways that can be cleaned up in the third patch.

-- 
Chandrabhanu Mahapatra
Texas Instruments India Pvt. Ltd.
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