Messages in this thread Patch in this message | | | Date | Mon, 25 Jun 2012 23:14:58 -0500 | From | Jonathan Nieder <> | Subject | [2.6.32.y] drm/i915: Attempt to fix watermark setup on 85x (v2) |
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From: Adam Jackson <ajax@redhat.com> Date: Fri, 16 Apr 2010 18:20:57 -0400
commit 8f4695ed1c9e068772bcce4cd4ff03f88d57a008 upstream.
IS_MOBILE() catches 85x, so we'd always try to use the 9xx FIFO sizing; since there's an explicit 85x version, this seems wrong.
v2: Handle 830m correctly too.
[jn: backport to 2.6.32.y to address https://bugzilla.kernel.org/show_bug.cgi?id=42839]
Signed-off-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> --- Hi Willy,
Lukas Anzinger wrote[1]:
> I've encountered a nasty bug in the drm/i915 part of Debian's stable kernel. > The code is also present in 2.6.33.20, which is the latest stable upstream > release of 2.6.33.y at the time of writing. > > During a refactoring of the i915 driver a regression has been introduced > (commit e70236a8d3d0a4c100a0b9f7d394d9bda9c56aca): For some chipsets the wrong > fifo size is determined which results in lot's of pixel errors when starting > the xserver and choosing 800x600 as a resolution. If another resolution is used > (eg. 1024x768 or 1280x1024), I don't encounter this problem.
Linux 2.6.32.y is presumably also affected because the problematic commit was applied during the 2.6.32 merge window.
e70236a8d3d0 "drm/i915: split display functions by chip type", 2009-09-21
Lukas tested the fix against a kernel with 2.6.33.y-based drm subsystem and found it to work:
8f4695ed1c9e drm/i915: Attempt to fix watermark setup on 85x (v2), 2010-04-16
and therefore Stefan is staging this fix for 2.6.32.y+drm33.z (thanks!). Newer stable lines work fine already because the fix hit mainline in v2.6.34-rc6.
The patch applies cleanly to v2.6.32.59 and is included below for reference. I don't know if anyone has tested it there, though. All I can say for now is that it is tested against 2.6.33-based kernels and looks obviously correct. What do you think?
Hope that helps, Jonathan
[1] https://bugzilla.kernel.org/show_bug.cgi?id=42839
drivers/gpu/drm/i915/intel_display.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 79cc437af3b8..25b3e903c67c 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -4355,17 +4355,18 @@ static void intel_init_display(struct drm_device *dev) dev_priv->display.update_wm = g4x_update_wm; else if (IS_I965G(dev)) dev_priv->display.update_wm = i965_update_wm; - else if (IS_I9XX(dev) || IS_MOBILE(dev)) { + else if (IS_I9XX(dev)) { dev_priv->display.update_wm = i9xx_update_wm; dev_priv->display.get_fifo_size = i9xx_get_fifo_size; + } else if (IS_I85X(dev)) { + dev_priv->display.update_wm = i9xx_update_wm; + dev_priv->display.get_fifo_size = i85x_get_fifo_size; } else { - if (IS_I85X(dev)) - dev_priv->display.get_fifo_size = i85x_get_fifo_size; - else if (IS_845G(dev)) + dev_priv->display.update_wm = i830_update_wm; + if (IS_845G(dev)) dev_priv->display.get_fifo_size = i845_get_fifo_size; else dev_priv->display.get_fifo_size = i830_get_fifo_size; - dev_priv->display.update_wm = i830_update_wm; } } -- 1.7.11.rc3
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