From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arkadiusz Miskiewicz <a.miskiewicz-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [Bug #14380] Video tearing/glitching with T400 laptops
Date: Tue, 17 Nov 2009 13:52:18 +0100
Message-ID: <200911171352.18563.a.miskiewicz@gmail.com>
References: <GUZt44bIwCE.A.vLF.pSdALB@chimera> <xXQGFmujPl.A.wG.6TdALB@chimera>
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To: "Rafael J. Wysocki" <rjw-KKrjLPT3xs0@public.gmane.org>
Cc: Linux Kernel Mailing List <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Kernel Testers List <kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Jesse Barnes <jbarnes-Y1mF5jBUw70BENJcbMCuUQ@public.gmane.org>, Theodore Ts'o <tytso-3s7WtUTddSA@public.gmane.org>

On Monday 16 of November 2009, Rafael J. Wysocki wrote:
> This message has been generated automatically as a part of a report
> of recent regressions.
>=20
> The following bug entry is on the current list of known regressions
> from 2.6.31.  Please verify if it still should be listed and let me k=
now
> (either way).

It's mostly gone. It still happens for like 1/4s once per 6hours but jb=
arnes
asked me to fill separate bug for that and gave such patch for testing =
(see below).

So far haven't seen 1/4s problem with this patch applied.

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i91=
5/intel_display.c
index 3ba6546..b2cbf7f 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2491,6 +2491,8 @@ static void g4x_update_wm(struct drm_device *dev,=
  int planea_clock,
                /* Use ns/us then divide to preserve precision */
                sr_entries =3D (((sr_latency_ns / line_time_us) + 1) *
                              pixel_size * sr_hdisplay) / 1000;
+               if (sr_entries > G4X_FIFO_SIZE)
+                       sr_entries =3D G4X_FIFO_SIZE;
                sr_entries =3D roundup(sr_entries / cacheline_size, 1);
                DRM_DEBUG("self-refresh entries: %d\n", sr_entries);
                I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN);

>=20
>=20
> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=3D14380
> Subject		: Video tearing/glitching with T400 laptops
> Submitter	: Theodore Ts'o <tytso-3s7WtUTddSA@public.gmane.org>
> Date		: 2009-10-02 22:40 (46 days old)
> References	: http://marc.info/?l=3Dlinux-kernel&m=3D125452324520623&w=
=3D4
> Handled-By	: Jesse Barnes <jbarnes-Y1mF5jBUw70BENJcbMCuUQ@public.gmane.org>
> Patch		: http://marc.info/?l=3Dlinux-kernel&m=3D125591495325000&w=3D4
>=20


--=20
Arkadiusz Mi=C5=9Bkiewicz        PLD/Linux Team
arekm / maven.pl            http://ftp.pld-linux.org/