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authorHans de Goede <hdegoede@redhat.com>2016-12-02 15:29:04 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-03-15 09:57:15 +0800
commit7952b6490bbce45e078c8c0e669df7a0a8f8948a (patch)
treee847b4a30822810714430f7025551416489a5b98
parent77fec8bc7a0fbee3bf5893d8c1ce755c029f2b40 (diff)
downloadlinux-linaro-stable-7952b6490bbce45e078c8c0e669df7a0a8f8948a.tar.gz
drm/i915/dsi: Do not clear DPOUNIT_CLOCK_GATE_DISABLE from vlv_init_display_clock_gating
commit bb98e72adaf9d19719aba35f802d4836f5d5176c upstream. On my Cherrytrail CUBE iwork8 Air tablet PIPE-A would get stuck on loading i915 at boot 1 out of every 3 boots, resulting in a non functional LCD. Once the i915 driver has successfully loaded, the panel can be disabled / enabled without hitting this issue. The getting stuck is caused by vlv_init_display_clock_gating() clearing the DPOUNIT_CLOCK_GATE_DISABLE bit in DSPCLK_GATE_D when called from chv_pipe_power_well_ops.enable() on driver load, while a pipe is enabled driving the DSI LCD by the BIOS. Clearing this bit while DSI is in use is a known issue and intel_dsi_pre_enable() / intel_dsi_post_disable() already set / clear it as appropriate. This commit modifies vlv_init_display_clock_gating() to leave the DPOUNIT_CLOCK_GATE_DISABLE bit alone fixing the pipe getting stuck. Changes in v2: -Replace PIPE-A with "a pipe" or "the pipe" in the commit msg and comment Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97330 Signed-off-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20161202142904.25613-1-hdegoede@redhat.com Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (cherry picked from commit 721d484563e1a51ada760089c490cbc47e909756) Signed-off-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: River Zhou <riverzhou2000@163.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/gpu/drm/i915/intel_pm.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 3f802163f7d4..e7c18519274a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -6803,7 +6803,18 @@ static void ivybridge_init_clock_gating(struct drm_device *dev)
static void vlv_init_display_clock_gating(struct drm_i915_private *dev_priv)
{
- I915_WRITE(DSPCLK_GATE_D, VRHUNIT_CLOCK_GATE_DISABLE);
+ u32 val;
+
+ /*
+ * On driver load, a pipe may be active and driving a DSI display.
+ * Preserve DPOUNIT_CLOCK_GATE_DISABLE to avoid the pipe getting stuck
+ * (and never recovering) in this case. intel_dsi_post_disable() will
+ * clear it when we turn off the display.
+ */
+ val = I915_READ(DSPCLK_GATE_D);
+ val &= DPOUNIT_CLOCK_GATE_DISABLE;
+ val |= VRHUNIT_CLOCK_GATE_DISABLE;
+ I915_WRITE(DSPCLK_GATE_D, val);
/*
* Disable trickle feed and enable pnd deadline calculation