[PATCH] drm/radeon/kms: fix tv dac conflict resolver

[GhePeU]

Il giorno dom, 02/05/2010 alle 20.46 +1000, Dave Airlie ha scritto:
> On Sun, May 2, 2010 at 7:42 PM, GhePeU <ghepeu at virgilio.it> wrote:
> > Il giorno dom, 02/05/2010 alle 19.11 +1000, Dave Airlie ha scritto:
> >> On Sat, May 1, 2010 at 10:42 PM, GhePeU <ghepeu at virgilio.it> wrote:
> >> > Il giorno mar, 27/04/2010 alle 18.57 -0400, Alex Deucher ha scritto:
> >> >> On Tue, Apr 27, 2010 at 6:24 PM, GhePeU <ghepeu at virgilio.it> wrote:
> >> >> > Il giorno mar, 27/04/2010 alle 18.11 -0400, Alex Deucher ha scritto:
> >> >> >> On Tue, Apr 27, 2010 at 5:30 PM, GhePeU <ghepeu at virgilio.it> wrote:
> >> >> >> > Il giorno gio, 15/04/2010 alle 13.41 -0400, Alex Deucher ha scritto:
> >> >> >> >> >From 837feb147c531219c7315857a6f17e145af8f750 Mon Sep 17 00:00:00 2001
> >> >> >> >> From: Alex Deucher <alexdeucher at gmail.com>
> >> >> >> >> Date: Thu, 15 Apr 2010 13:31:12 -0400
> >> >> >> >> Subject: [PATCH] drm/radeon/kms: fix tv dac conflict resolver
> >> >> >> >
> >> >> >> > Hi,
> >> >> >> >
> >> >> >> > a few days ago I upgraded to the last 2.6.34 rc kernel and found that with
> >> >> >> > KMS both the console and X were using a 800x600 resolution instead of my LCD
> >> >> >> > display's native resolution of 1440x900 who was selected by default with
> >> >> >> > 2.6.33 and previous kernels.
> >> >> >> >
> >> >> >> > I tracked the problem to this patch, which causes the same issues also
> >> >> >> > when manually applied to 2.6.33: apparently the kms radeon driver
> >> >> >> > wrongly detects a TV connected to my card (I don't have one, only a LCD
> >> >> >> > display connected to the DVI port) and forces the TV default resolution
> >> >> >> > for all the outputs.
> >> >> >>
> >> >> >> You issue is not related to the patch.  What the patch does is allow
> >> >> >> you to use the digital part of DVI plus TV at the same time.  The
> >> >> >> analog part of the DVI port and the TV share the same DAC so they
> >> >> >> can't be used at the same time.  Prior to the patch, both the TV and
> >> >> >> DVI were detected as attached, but the TV was always disabled since it
> >> >> >> was wrongly seen as conflicting with the DVI.
> >> >> >>
> >> >> >> Your issue is actually a matter of load detection for TV not always
> >> >> >> being reliable.  I don't know what a proper fix would be.  We could
> >> >> >> disable load detection for TV to avoid false positives, but that would
> >> >> >> prevent automatic detection of TV which does work in most cases.
> >> >> >>
> >> >> >> Alex
> >> >> >>
> >> >> >
> >> >> > With UMS however I don't have this problem, is the logic different?
> >> >> >
> >> >> > Shouldn't the driver behavior with KMS be the same, in this case? At
> >> >> > least there wouldn't be (apparent) regressions like the one I'm
> >> >> > experiencing.
> >> >> >
> >> >>
> >> >> UMS does not enable load detection on TV by default while KMS does,
> >> >> the difference being KMS provides both the console and X so you want
> >> >> to make sure you put something up on whatever monitors or tvs happen
> >> >> to be attached.  I'm not sure what the best answer is here.
> >> >>
> >> >> Alex
> >> >
> >> > Would it be possible to add a module option to disable tv load
> >> > detection? As things are now I must always change back the resolution to
> >> > 1440x900 and disable the TV.
> >>
> >> try booting with video=TV-1:d
> 
> oh try video=DIN-1:d
> 
> or S-video-1:d, have a look in /sys/class/drm when booted for the correct one.
> 
> Dave.

/sys/class/drm lists "card0-SVIDEO-1", dmesg has "S-video" and the
encoder is "TV1". I booted with "video=SVIDEO-1:d", "video=S-video:d",
"video=TV1:d" and finally "video=S-video-1:d" but none of them worked.

I'll look to the source code when I'll have the time.

Giacomo