[Natty,SRU] drm/i915: fix CB tuning check for ILK+

Message ID 4EC4F041.1030506@ubuntu.com
State New
Headers show

Commit Message

Timo Aaltonen Nov. 17, 2011, 11:30 a.m.
17.11.2011 13:26, Stefan Bader kirjoitti:
> On 16.11.2011 10:45, TImo Aaltonen wrote:
>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/891031
>> This patch fixes panel corruption on my T420s which occurs after
>> plugging an external monitor to the vga port. Originally from 3.1,
>> applies to 3.0 too but I'll post this upstream to include in the stable
>> series.
>> upstream commit cb0e093162d7b6589c2217a00e2abfef686b32d6
>> Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>
> Having the maintainer agreeing is good. So I tried to go forward and get the
> patch into Natty. But the submitted patch does not apply to Natty. While it can
> be resolved that looks ok, it makes me a bit suspicious about the having tested
> part for Natty... Attached is the backport version (also including the
> signed-off-by block in the style we would like to see in submitted patches
> (without the acks of course)). Is that what got really tested?

Oops, yes.. I had a backported version locally which I used, but
attached the upstream commit. Sorry about that! Attached is the correct
one, and as you can see it's identical to yours :)


commit cb0e093162d7b6589c2217a00e2abfef686b32d6
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Jul 28 14:50:30 2011 -0700

    drm/i915: fix CB tuning check for ILK+
    CB tuning is needed to handle potential process variations that might
    cause clock jitter for certain PLL settings.  However, we were setting
    it incorrectly since we were using the wrong M value as a check (M1 when
    we needed to use the whole M value).  Fix it up, making my HDMI
    attached display a little prettier (used to have occasional dots crawl
    across the display).
    Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
    Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 8f7ed73..32c8c95 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4994,7 +4994,7 @@  static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
 	} else if (is_sdvo && is_tv)
 		factor = 20;
-	if (clock.m1 < factor * clock.n)
+	if (clock.m < factor * clock.n)
 		fp |= FP_CB_TUNE;
 	dpll = 0;