[PATCH] viafb: correct sync polarity for OLPC DCON

Subsystems: framebuffer layer, the rest

STALE5366d

2 messages, 2 authors, 2011-11-23 · open the first message on its own page

[PATCH] viafb: correct sync polarity for OLPC DCON

From: Daniel Drake <hidden>
Date: 2011-11-21 15:05:56

While the OLPC display appears to be able to handle either positive
or negative sync, the Display Controller only recognises positive sync.

This brings viafb (for XO-1.5) in line with lxfb (for XO-1) and
fixes a recent regression where the XO-1.5 DCON could no longer be
frozen. Thanks to Florian Tobias Schandinat for helping identify
the fix.

Test case: from a vt,
	echo 1 > /sys/devices/platform/dcon/freeze
should cause the current screen contents to freeze, rather than garbage being
displayed.

Signed-off-by: Daniel Drake <redacted>
---
 drivers/video/via/share.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/via/share.h b/drivers/video/via/share.h
index 69d882c..c01c1c1 100644
--- a/drivers/video/via/share.h
+++ b/drivers/video/via/share.h
@@ -559,8 +559,8 @@
 #define M1200X720_R60_VSP       POSITIVE
 
 /* 1200x900@60 Sync Polarity (DCON) */
-#define M1200X900_R60_HSP       NEGATIVE
-#define M1200X900_R60_VSP       NEGATIVE
+#define M1200X900_R60_HSP       POSITIVE
+#define M1200X900_R60_VSP       POSITIVE
 
 /* 1280x600@60 Sync Polarity (GTF Mode) */
 #define M1280x600_R60_HSP       NEGATIVE
-- 
1.7.7.3

Re: [PATCH] viafb: correct sync polarity for OLPC DCON

From: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Date: 2011-11-23 06:53:42

On 11/21/2011 03:05 PM, Daniel Drake wrote:
While the OLPC display appears to be able to handle either positive
or negative sync, the Display Controller only recognises positive sync.

This brings viafb (for XO-1.5) in line with lxfb (for XO-1) and
fixes a recent regression where the XO-1.5 DCON could no longer be
frozen. Thanks to Florian Tobias Schandinat for helping identify
the fix.

Test case: from a vt,
	echo 1 > /sys/devices/platform/dcon/freeze
should cause the current screen contents to freeze, rather than garbage being
displayed.

Signed-off-by: Daniel Drake <redacted>
Applied.


Thanks,

Florian Tobias Schandinat
quoted hunk
---
 drivers/video/via/share.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/video/via/share.h b/drivers/video/via/share.h
index 69d882c..c01c1c1 100644
--- a/drivers/video/via/share.h
+++ b/drivers/video/via/share.h
@@ -559,8 +559,8 @@
 #define M1200X720_R60_VSP       POSITIVE
 
 /* 1200x900@60 Sync Polarity (DCON) */
-#define M1200X900_R60_HSP       NEGATIVE
-#define M1200X900_R60_VSP       NEGATIVE
+#define M1200X900_R60_HSP       POSITIVE
+#define M1200X900_R60_VSP       POSITIVE
 
 /* 1280x600@60 Sync Polarity (GTF Mode) */
 #define M1280x600_R60_HSP       NEGATIVE

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