[PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor
On Wed, 30 Mar 2016, Ville Syrjälä wrote:
> On Sat, Mar 26, 2016 at 01:18:38PM +, Paul Parsons wrote:
>> The EDID 1.4 specification section 3.10.3.9 defines an Established Timings
>> III
>> descriptor (tag #F7h). The parsing of this descriptor by drm_est3_modes() is
>> off by one byte: the offset of the first timing bitmap is 6, not 5.
>>
>> Signed-off-by: Paul Parsons
>> ---
>>
>> diff -ru a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
>> --- a/drivers/gpu/drm/drm_edid.c 2016-03-14 04:28:54.0 +
>> +++ b/drivers/gpu/drm/drm_edid.c 2016-03-26 12:04:58.963352156 +
>> @@ -2215,7 +2215,7 @@
>> {
>> int i, j, m, modes = 0;
>> struct drm_display_mode *mode;
>> -u8 *est = ((u8 *)timing) + 5;
>> +u8 *est = ((u8 *)timing) + 6;
>
> Hmm. The code is very hard to follow due to the weird structs and
> whatnot. But yeah this looks correct.
>
> Reviewed-by: Ville Syrjälä
Pushed to our topic/drm-fixes, thanks for the patch and review.
BR,
Jani.
>
> Oh and I suppose you could also fix up the EDID version check
> to check for 1.4+ before even considering the est3 descriptor
> as valid.
>
>>
>> for (i = 0; i < 6; i++) {
>> for (j = 7; j >= 0; j--) {
>>
>>
>>
>> ___
>> dri-devel mailing list
>> dri-devel at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Jani Nikula, Intel Open Source Technology Center
[PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor
On Sat, Mar 26, 2016 at 01:18:38PM +, Paul Parsons wrote:
> The EDID 1.4 specification section 3.10.3.9 defines an Established Timings III
> descriptor (tag #F7h). The parsing of this descriptor by drm_est3_modes() is
> off by one byte: the offset of the first timing bitmap is 6, not 5.
>
> Signed-off-by: Paul Parsons
> ---
>
> diff -ru a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> --- a/drivers/gpu/drm/drm_edid.c 2016-03-14 04:28:54.0 +
> +++ b/drivers/gpu/drm/drm_edid.c 2016-03-26 12:04:58.963352156 +
> @@ -2215,7 +2215,7 @@
> {
> int i, j, m, modes = 0;
> struct drm_display_mode *mode;
> - u8 *est = ((u8 *)timing) + 5;
> + u8 *est = ((u8 *)timing) + 6;
Hmm. The code is very hard to follow due to the weird structs and
whatnot. But yeah this looks correct.
Reviewed-by: Ville Syrjälä
Oh and I suppose you could also fix up the EDID version check
to check for 1.4+ before even considering the est3 descriptor
as valid.
>
> for (i = 0; i < 6; i++) {
> for (j = 7; j >= 0; j--) {
>
>
>
> ___
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Ville Syrjälä
Intel OTC
[PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor
On Sun, 27 Mar 2016, Paul Parsons wrote: > The EDID 1.4 specification section 3.10.3.9 defines an Established Timings III > descriptor (tag #F7h). The parsing of this descriptor by drm_est3_modes() is > off by one byte: the offset of the first timing bitmap is 6, not 5. Dupe? Let's keep the discussion in [1]. BR, Jani. [1] http://mid.gmane.org/20160328002258.E75DF6E35D at gabe.freedesktop.org -- Jani Nikula, Intel Open Source Technology Center
[PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor
On Sat, 26 Mar 2016, Paul Parsons wrote:
> The EDID 1.4 specification section 3.10.3.9 defines an Established Timings III
> descriptor (tag #F7h). The parsing of this descriptor by drm_est3_modes() is
> off by one byte: the offset of the first timing bitmap is 6, not 5.
>
> Signed-off-by: Paul Parsons
I'm not all that familiar with the EDID parsing code, but this seems
right.
Reviewed-by: Jani Nikula
I'd appreciate an extra set of eyeballs on this one still.
Makes you wonder about the implications though. We've been reading the
revision number as a bitmask and otherwise been off by one byte. The
interpretation of Established Timings III would have been pretty much
random. Where are the bugs?
BR,
Jani.
> ---
>
> diff -ru a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> --- a/drivers/gpu/drm/drm_edid.c 2016-03-14 04:28:54.0 +
> +++ b/drivers/gpu/drm/drm_edid.c 2016-03-26 12:04:58.963352156 +
> @@ -2215,7 +2215,7 @@
> {
> int i, j, m, modes = 0;
> struct drm_display_mode *mode;
> - u8 *est = ((u8 *)timing) + 5;
> + u8 *est = ((u8 *)timing) + 6;
>
> for (i = 0; i < 6; i++) {
> for (j = 7; j >= 0; j--) {
>
>
>
> ___
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Jani Nikula, Intel Open Source Technology Center
[PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor
The EDID 1.4 specification section 3.10.3.9 defines an Established Timings III
descriptor (tag #F7h). The parsing of this descriptor by drm_est3_modes() is
off by one byte: the offset of the first timing bitmap is 6, not 5.
Signed-off-by: Paul Parsons
---
diff -ru a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
--- a/drivers/gpu/drm/drm_edid.c2016-03-14 04:28:54.0 +
+++ b/drivers/gpu/drm/drm_edid.c2016-03-26 12:04:58.963352156 +
@@ -2215,7 +2215,7 @@
{
int i, j, m, modes = 0;
struct drm_display_mode *mode;
- u8 *est = ((u8 *)timing) + 5;
+ u8 *est = ((u8 *)timing) + 6;
for (i = 0; i < 6; i++) {
for (j = 7; j >= 0; j--) {
[PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor
The EDID 1.4 specification section 3.10.3.9 defines an Established Timings III
descriptor (tag #F7h). The parsing of this descriptor by drm_est3_modes() is
off by one byte: the offset of the first timing bitmap is 6, not 5.
Signed-off-by: Paul Parsons
---
diff -ru a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
--- a/drivers/gpu/drm/drm_edid.c2016-03-14 04:28:54.0 +
+++ b/drivers/gpu/drm/drm_edid.c2016-03-26 12:04:58.963352156 +
@@ -2215,7 +2215,7 @@
{
int i, j, m, modes = 0;
struct drm_display_mode *mode;
- u8 *est = ((u8 *)timing) + 5;
+ u8 *est = ((u8 *)timing) + 6;
for (i = 0; i < 6; i++) {
for (j = 7; j >= 0; j--) {
