[PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor

[Jani Nikula]

On Wed, 30 Mar 2016, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Sat, Mar 26, 2016 at 01:18:38PM +0000, 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 <lost.distance at yahoo.com>
>> ---
>> 
>> 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 04:28:54.000000000 +0000
>> +++ b/drivers/gpu/drm/drm_edid.c	2016-03-26 12:04:58.963352156 +0000
>> @@ -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 <ville.syrjala at linux.intel.com>

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--) {
>> 
>> 
>> 
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-- 
Jani Nikula, Intel Open Source Technology Center