On 04/20/2015 03:28 PM, Chris Wilson wrote:
The intention of using video=<connector>:<mode> is primarily to select the user's preferred resolution at startup. Currently we always create 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 fake 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. Oops. This invalid fake mode would also be exported to userspace, who potentially may make the same mistake.
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.
A second issue sneaked into this patch is to add the cmdline mode mode 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.
Fixes regression from
commit eaf99c749d43ae74ac7ffece5512f3c73f01dfd2 Author: Chris Wilson chris@chris-wilson.co.uk Date: Wed Aug 6 10:08:32 2014 +0200
drm: Perform cmdline mode parsing during connector initialisationthat breaks HDMI output on BeagleBone Black with LG TV (model 19LS4R-ZA).
v2: Explicitly delete our earlier cmdline mode
Reported-by: Radek Dostál rd@radekdostal.com Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Radek Dostál rd@radekdostal.com Cc: Jesse Barnes jbarnes@virtuousgeek.org Cc: Ville Syrjälä 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 Dostál rd@radekdostal.com
Thanks, Radek