From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?UTF-8?B?UmFkZWsgRG9zdMOhbA==?= <rd@radekdostal.com>
Subject: Re: [PATCH v2] drm: Only create a cmdline mode if no probed modes
 match
Date: Mon, 20 Apr 2015 15:41:48 +0200
Message-ID: <5535021C.1030801@radekdostal.com>
References: <5534F9D6.4080908@radekdostal.com> <1429536536-4107-1-git-send-email-chris@chris-wilson.co.uk>
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To: Chris Wilson <chris@chris-wilson.co.uk>, dri-devel@lists.freedesktop.org
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>, =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= <ville.syrjala@linux.intel.com>, Daniel Vetter <daniel.vetter@ffwll.ch>, Julia Lemire <jlemire@matrox.com>, Dave Airlie <airlied@redhat.com>, stable@vger.kernel.org
List-Id: dri-devel@lists.freedesktop.org

On 04/20/2015 03:28 PM, Chris Wilson wrote:
> The intention of using video=3D<connector>:<mode> is primarily to sel=
ect
> the user's preferred resolution at startup. Currently we always creat=
e a
> new mode irrespective of whether the monitor has a native mode at the
> desired resolution. This has the issue that we may then select the fa=
ke
> mode rather the native mode during fb_helper->inital_config() and so
> if the fake mode is invalid we then end up with a loss of signal. Oop=
s.
> This invalid fake mode would also be exported to userspace, who
> potentially may make the same mistake.
>=20
> To avoid this issue, we filter out the added command line mode if we
> detect the desired resolution (and clock if specified) amongst the
> probed modes. This fixes the immediate problem of adding a duplicate
> mode, but perhaps more generically we should avoid adding a GTF mode =
if
> the monitor has an EDID that is not GTF-compatible, or similarly for
> CVT.
>=20
> A second issue sneaked into this patch is to add the cmdline mode mod=
e
> ahead of the absolute fallback 1024x768 mode. That is if the user has
> specified a mode that we create as a fallback, we do not need to add =
a
> second unused fallback mode.
>=20
> Fixes regression from
>=20
> commit eaf99c749d43ae74ac7ffece5512f3c73f01dfd2
> Author: Chris Wilson <chris@chris-wilson.co.uk>
> Date:   Wed Aug 6 10:08:32 2014 +0200
>=20
>     drm: Perform cmdline mode parsing during connector initialisation
>=20
> that breaks HDMI output on BeagleBone Black with LG TV (model 19LS4R-=
ZA).
>=20
> v2: Explicitly delete our earlier cmdline mode
>=20
> Reported-by: Radek Dost=C3=A1l <rd@radekdostal.com>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Radek Dost=C3=A1l <rd@radekdostal.com>
> Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> Cc: Ville Syrj=C3=A4l=C3=A4 <ville.syrjala@linux.intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: dri-devel@lists.freedesktop.org
> Cc: Julia Lemire <jlemire@matrox.com>
> Cc: Dave Airlie <airlied@redhat.com>
> Cc: stable@vger.kernel.org

works now :)

Tested-by: Radek Dost=C3=A1l <rd@radekdostal.com>

Thanks,
Radek