drm/i915: fix CB tuning check for ILK+

commit cb0e093162d7b6589c2217a00e2abfef686b32d6 upstream.

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>
Signed-off-by: Timo Aaltonen <timo@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3976909b5dc5fd83aa0b82775cc43743ef662291..fed87d6a5b99798e17c8b47871cfed491cdb39f4 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4972,7 +4972,7 @@ 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;