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From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Paul Parsons <lost.distance@yahoo.com>
Cc: dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor
Date: Wed, 30 Mar 2016 16:19:44 +0300	[thread overview]
Message-ID: <20160330131944.GL4329@intel.com> (raw)
In-Reply-To: <20160328002258.E75DF6E35D@gabe.freedesktop.org>

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@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@linux.intel.com>

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@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Ville Syrjälä
Intel OTC
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  parent reply	other threads:[~2016-03-30 13:19 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-26 13:18 [PATCH] drm/edid: Fix parsing of EDID 1.4 Established Timings III descriptor Paul Parsons
2016-03-30  9:45 ` Jani Nikula
2016-03-30 13:19 ` Ville Syrjälä [this message]
2016-04-05 10:27   ` Jani Nikula
  -- strict thread matches above, loose matches on Subject: below --
2016-03-27 11:15 Paul Parsons
2016-03-30 10:10 ` Jani Nikula

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