linux-kernel - Re: Radeon jittery post 2.6.35

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 15 Mar 2011 21:58:35 +0100
From:	Anders Eriksson <aeriksson@...tmail.fm>
To:	Alex Deucher <alexdeucher@...il.com>
CC:	airlied@...hat.com, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org, xorg-driver-ati@...ts.x.org
Subject: Re: Radeon jittery post 2.6.35

 On 03/14/11 23:22, Alex Deucher wrote:
> On Mon, Mar 14, 2011 at 6:20 PM, Alex Deucher <alexdeucher@...il.com> wrote:
> > On Sun, Mar 13, 2011 at 10:08 AM, Anders Eriksson <aeriksson@...tmail.fm> wrote:
> >>  Hi,
> >>
> >> I've found what I guess is a radeon (or drm/kms) regression post 2.6.35.
> >> I've got my TV conneced to my RS690G over HDMI, and the display has
> >> always been jittery after POST and at the GRUB screen. Pre-KMS, the X
> >> server (or driver got it sorted), and when KMS started, the display
> >> stabilized right after the kernel driver was initiated. However, post
> >> 2.6.35, I see the jitter is back.
> >>
> >> I've spent the last month trying to bisect it, but pretty much failed.
> >> It appears that versions closer to 2.6.38-rcX are more prone to display
> >> jitter, while 2.6.36 or so can have many successful runs. It also
> >> appears to be related to device power-on order, or so I've come to
> >> believe; A stable display can turn jittery, just by power cycling the TV.
> >>

Some further testing on a clean rc8 suggests that the jitter seen
there can  reliably be removed by power cycling the TV while in X,
or starting X with the TV off.

I'm tempted to think that something makes too much out of bad
info collected from the TV, and falls backs to saner defaults if
the TV has nothing to say.

I've seen in the logs that the EDID is disliked:
[drm:radeon_dvi_detect] *ERROR* HDMI-A-1: probed a monitor but
no|invalid EDID
Not sure if that is related though (cannot seem to be able to provoke
that error message right now)

-A



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/