[PATCH] drm/i915: i915.disable_pch_pwm overrides PCH_PWM_ENABLE quirk

From: Kamal Mostafa
Date: Tue Sep 03 2013 - 13:37:45 EST


BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=47941

Some BIOS configurations of Dell XPS13 are adversely affected by e85843b
("drm/i915: quirk no PCH_PWM_ENABLE for Dell XPS13 backlight") so provide a
boot param to inhibit the quirk, or force it on.

i915.disable_pch_pwm can be set to
-1: auto (default; allows the disabling of pch_pwm by dmi quirk table match)
0: inhibits the disabling of pch_pwm (overrides dmi quirk table match)
1: forces the disabling of pch_pwm

Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.c | 4 ++++
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/intel_display.c | 11 ++++++++---
3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 72e2be7..fee05df 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -154,6 +154,10 @@ module_param_named(prefault_disable, i915_prefault_disable, bool, 0600);
MODULE_PARM_DESC(prefault_disable,
"Disable page prefaulting for pread/pwrite/reloc (default:false). For developers only.");

+int i915_disable_pch_pwm __read_mostly = -1;
+module_param_named(disable_pch_pwm, i915_disable_pch_pwm, int, 0600);
+MODULE_PARM_DESC(disable_pch_pwm, "disable PCH_PWM (default: -1 (auto))");
+
static struct drm_driver driver;
extern int intel_agp_enabled;

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 769c138..e6f2a34 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1726,6 +1726,7 @@ extern bool i915_fastboot __read_mostly;
extern int i915_enable_pc8 __read_mostly;
extern int i915_pc8_timeout __read_mostly;
extern bool i915_prefault_disable __read_mostly;
+extern int i915_disable_pch_pwm __read_mostly;

extern int i915_suspend(struct drm_device *dev, pm_message_t state);
extern int i915_resume(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 30e5946..86fa722 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9948,9 +9948,8 @@ static void quirk_invert_brightness(struct drm_device *dev)
*/
static void quirk_no_pcm_pwm_enable(struct drm_device *dev)
{
- struct drm_i915_private *dev_priv = dev->dev_private;
- dev_priv->quirks |= QUIRK_NO_PCH_PWM_ENABLE;
- DRM_INFO("applying no-PCH_PWM_ENABLE quirk\n");
+ if (i915_disable_pch_pwm < 0)
+ i915_disable_pch_pwm = 1;
}

struct intel_quirk {
@@ -10048,6 +10047,12 @@ static void intel_init_quirks(struct drm_device *dev)
if (dmi_check_system(*intel_dmi_quirks[i].dmi_id_list) != 0)
intel_dmi_quirks[i].hook(dev);
}
+
+ if (i915_disable_pch_pwm == 1) {
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ dev_priv->quirks |= QUIRK_NO_PCH_PWM_ENABLE;
+ DRM_INFO("applying no-PCH_PWM_ENABLE quirk\n");
+ }
}

/* Disable the VGA plane that we never use */
--
1.8.1.2

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