From: Jani Nikula <jani.nikula@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: jani.nikula@intel.com, ying.huang@intel.com
Subject: [PATCH RESEND] drm/i915: disable CPU PWM also on LPT/SPT backlight disable
Date: Wed, 28 Oct 2015 13:57:09 +0200 [thread overview]
Message-ID: <1446033429-8006-1-git-send-email-jani.nikula@intel.com> (raw)
Although we don't support or enable CPU PWM with LPT/SPT based systems,
it may have been enabled prior to loading the driver. Disable the CPU
PWM on LPT/SPT backlight disable to avoid warnings on LCPLL disable.
The issue has been present on BDW since BDW enabling, but was recently
introduced on HSW with
commit 437b15b8017e0d946453c10794b0c5d4591cf180
Author: Jani Nikula <jani.nikula@intel.com>
Date: Fri Sep 4 16:55:13 2015 +0300
drm/i915: use pch backlight override on hsw too
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reference: http://mid.gmane.org/87y4frhwsn.fsf@yhuang-dev.intel.com
Reported-by: kernel test robot <ying.huang@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
drivers/gpu/drm/i915/intel_panel.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index b05c6d9b3be7..a24df35e11e7 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -732,6 +732,20 @@ static void lpt_disable_backlight(struct intel_connector *connector)
intel_panel_actually_set_backlight(connector, 0);
+ /*
+ * Although we don't support or enable CPU PWM with LPT/SPT based
+ * systems, it may have been enabled prior to loading the
+ * driver. Disable to avoid warnings on LCPLL disable.
+ *
+ * This needs rework if we need to add support for CPU PWM on PCH split
+ * platforms.
+ */
+ tmp = I915_READ(BLC_PWM_CPU_CTL2);
+ if (tmp & BLM_PWM_ENABLE) {
+ DRM_DEBUG_KMS("cpu backlight was enabled, disabling\n");
+ I915_WRITE(BLC_PWM_CPU_CTL2, tmp & ~BLM_PWM_ENABLE);
+ }
+
tmp = I915_READ(BLC_PWM_PCH_CTL1);
I915_WRITE(BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
}
--
2.1.4
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next reply other threads:[~2015-10-28 11:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-28 11:57 Jani Nikula [this message]
2015-10-28 16:42 ` [PATCH RESEND] drm/i915: disable CPU PWM also on LPT/SPT backlight disable Ville Syrjälä
2015-10-28 17:12 ` Jani Nikula
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