From: Hette Visser Date: Fri, 24 Sep 2010 09:51:30 +0000 (+0100) Subject: drm/i915/dp: Wait for PP_CONTROL to take effect. X-Git-Tag: firefly_0821_release~7613^2~3600^2~31^2~41 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=27d64339a8d8465484286a2da93f5f6c36be5c3d;p=firefly-linux-kernel-4.4.55.git drm/i915/dp: Wait for PP_CONTROL to take effect. This patch fixes the black screen bug on Dell e6510, by adding two delays to give the eDP panel time to turn on before we continue with the next write. 300ms is rather arbitray and a rather long sleep, we need to find a way of refining this value. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29278 Signed-off-by: Chris Wilson Acked-by: Jesse Barnes --- diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 117eb9988250..d19334aa66ad 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -784,6 +784,11 @@ static bool ironlake_edp_panel_on (struct drm_device *dev) pp |= POWER_TARGET_ON; I915_WRITE(PCH_PP_CONTROL, pp); + /* Ouch. We need to wait here for some panels, like Dell e6510 + * https://bugs.freedesktop.org/show_bug.cgi?id=29278i + */ + msleep(300); + if (wait_for(I915_READ(PCH_PP_STATUS) & PP_ON, 5000)) DRM_ERROR("panel on wait timed out: 0x%08x\n", I915_READ(PCH_PP_STATUS)); @@ -819,6 +824,11 @@ static void ironlake_edp_panel_off (struct drm_device *dev) pp |= PANEL_POWER_RESET; /* restore panel reset bit */ I915_WRITE(PCH_PP_CONTROL, pp); POSTING_READ(PCH_PP_CONTROL); + + /* Ouch. We need to wait here for some panels, like Dell e6510 + * https://bugs.freedesktop.org/show_bug.cgi?id=29278i + */ + msleep(300); } static void ironlake_edp_panel_vdd_on(struct drm_device *dev)