video: vt8500: Fix X crash when initializing framebuffer.

This patch adds support for .fb_check_var which is required when
X attempts to initialize the framebuffer. The only supported
resolution is the native resolution of the LCD panel, so we test
against the resolution supplied from the DT panel definition.

Signed-off-by: Tony Prisk <redacted>
---
 drivers/video/wm8505fb.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/video/wm8505fb.c b/drivers/video/wm8505fb.c
index 77539c1..c84e376 100644
--- a/drivers/video/wm8505fb.c
+++ b/drivers/video/wm8505fb.c

@@ -41,10 +41,18 @@
 
 #define to_wm8505fb_info(__info) container_of(__info, \
 						struct wm8505fb_info, fb)
+
+struct lcd_params {
+	u32 pixel_width;
+	u32 pixel_height;
+	u32 color_depth;
+};
+
 struct wm8505fb_info {
 	struct fb_info		fb;
 	void __iomem		*regbase;
 	unsigned int		contrast;
+	struct lcd_params	lcd_params;
 };
 
 

@@ -248,8 +256,21 @@ static int wm8505fb_blank(int blank, struct fb_info *info)
 	return 0;
 }
 
+static int wm8505fb_check_var(struct fb_var_screeninfo *var,
+			      struct fb_info *info)
+{
+	struct wm8505fb_info *fbi = to_wm8505fb_info(info);
+        if (!fbi) return -EINVAL;
+
+	if (info->var.bits_per_pixel != fbi->lcd_params.color_depth) return -EINVAL;
+	if (info->var.xres != fbi->lcd_params.pixel_width) return -EINVAL;
+	if (info->var.yres != fbi->lcd_params.pixel_height) return -EINVAL;
+	return 0;
+}
+
 static struct fb_ops wm8505fb_ops = {
 	.owner		= THIS_MODULE,
+	.fb_check_var	= wm8505fb_check_var,
 	.fb_set_par	= wm8505fb_set_par,
 	.fb_setcolreg	= wm8505fb_setcolreg,
 	.fb_fillrect	= wmt_ge_fillrect,

@@ -354,6 +375,10 @@ static int __devinit wm8505fb_probe(struct platform_device *pdev)
 		goto failed_free_res;
 	}
 
+	fbi->lcd_params.pixel_width = of_mode.xres;
+	fbi->lcd_params.pixel_height = of_mode.yres;
+	fbi->lcd_params.color_depth = bpp;
+
 	of_mode.vmode = FB_VMODE_NONINTERLACED;
 	fb_videomode_to_var(&fbi->fb.var, &of_mode);
 

-- 
1.7.9.5

On 12/27/2012 12:25 AM, Tony Prisk wrote:

This patch adds support for .fb_check_var which is required when
X attempts to initialize the framebuffer. The only supported
resolution is the native resolution of the LCD panel, so we test
against the resolution supplied from the DT panel definition.

Nack. As far as I understand this driver behaves as it is supposed to do
according to drivers/video/skeletonfb.c. The frambuffer code seems to do
what is documented as well. If the X driver cannot cope with a different
var set than requested it needs to be fixed anyway as check_var is
always allowed to alter the parameters requested.
Strange, I thought I already saw X complaining about this when I added
30bpp mode to viafb.


Best regards,

Florian Tobias Schandinat

22 more quoted lines

Hello.

On 12/27/2012 03:25 AM, Tony Prisk wrote:

This patch adds support for .fb_check_var which is required when
X attempts to initialize the framebuffer. The only supported
resolution is the native resolution of the LCD panel, so we test
against the resolution supplied from the DT panel definition.

Signed-off-by: Tony Prisk <redacted>
---
 drivers/video/wm8505fb.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

[...]

[...]

$ scripts/checkpatch.pl
patches/video-vt8500-Fix-X-crash-when-initializing-framebuffer.patch
ERROR: code indent should use tabs where possible
#42: FILE: drivers/video/wm8505fb.c:263:
+        if (!fbi) return -EINVAL;$

WARNING: please, no spaces at the start of a line
#42: FILE: drivers/video/wm8505fb.c:263:
+        if (!fbi) return -EINVAL;$

ERROR: trailing statements should be on next line
#42: FILE: drivers/video/wm8505fb.c:263:
+        if (!fbi) return -EINVAL;

WARNING: line over 80 characters
#44: FILE: drivers/video/wm8505fb.c:265:
+	if (info->var.bits_per_pixel != fbi->lcd_params.color_depth) return -EINVAL;

ERROR: trailing statements should be on next line
#44: FILE: drivers/video/wm8505fb.c:265:
+	if (info->var.bits_per_pixel != fbi->lcd_params.color_depth) return -EINVAL;

ERROR: trailing statements should be on next line
#45: FILE: drivers/video/wm8505fb.c:266:
+	if (info->var.xres != fbi->lcd_params.pixel_width) return -EINVAL;

ERROR: trailing statements should be on next line
#46: FILE: drivers/video/wm8505fb.c:267:
+	if (info->var.yres != fbi->lcd_params.pixel_height) return -EINVAL;

total: 5 errors, 2 warnings, 49 lines checked

NOTE: whitespace errors detected, you may wish to use scripts/cleanpatch or
      scripts/cleanfile

patches/video-vt8500-Fix-X-crash-when-initializing-framebuffer.patch has style
problems, please review.

6 more lines