On Wed, Apr 25, 2012 at 10:28:41AM -0700, Kamal Mostafa wrote: > i915.enable_backlight=0 can be used to disable i915 backlight control > and the /sys/class/backlight/intel_backlight interface -- useful for > systems where intel_backight conflicts with BIOS backlight control. > > BugLink: https://launchpad.net/bugs/954661 > Signed-off-by: Kamal Mostafa <kamal at canonical.com> Ok, I've just gone through the fun of merging a set of backlight quirks a few weeks back. Then noticed that an awful lot of machines seem to be affected and later on read about a few interesting bits in the documentation. Turns out the hw is all good, it's just the driver totally mishandling the backlight. To cut things short: This time around I want more justification for the quirk than just "this makes this one machine work somehow". -Daniel > --- > drivers/gpu/drm/i915/i915_drv.c | 6 ++++++ > drivers/gpu/drm/i915/i915_drv.h | 1 + > drivers/gpu/drm/i915/intel_panel.c | 12 ++++++++++++ > 3 files changed, 19 insertions(+), 0 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c > index ae8a64f..ddb947b 100644 > --- a/drivers/gpu/drm/i915/i915_drv.c > +++ b/drivers/gpu/drm/i915/i915_drv.c > @@ -112,6 +112,12 @@ module_param_named(i915_enable_ppgtt, i915_enable_ppgtt, int, 0600); > MODULE_PARM_DESC(i915_enable_ppgtt, > "Enable PPGTT (default: true)"); > > +int i915_enable_backlight __read_mostly = -1; > +module_param_named(enable_backlight, i915_enable_backlight, int, 0644); > +MODULE_PARM_DESC(enable_backlight, > + "Enable backlight control and the intel_backlight interface. " > + "(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 5fabc6c..6e52a42 100644 > --- a/drivers/gpu/drm/i915/i915_drv.h > +++ b/drivers/gpu/drm/i915/i915_drv.h > @@ -1087,6 +1087,7 @@ extern int i915_enable_rc6 __read_mostly; > extern int i915_enable_fbc __read_mostly; > extern bool i915_enable_hangcheck __read_mostly; > extern int i915_enable_ppgtt __read_mostly; > +extern int i915_enable_backlight __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_panel.c b/drivers/gpu/drm/i915/intel_panel.c > index 48177ec..fcecbd2 100644 > --- a/drivers/gpu/drm/i915/intel_panel.c > +++ b/drivers/gpu/drm/i915/intel_panel.c > @@ -259,6 +259,9 @@ void intel_panel_disable_backlight(struct drm_device *dev) > { > struct drm_i915_private *dev_priv = dev->dev_private; > > + if (!i915_enable_backlight) > + return; > + > dev_priv->backlight_enabled = false; > intel_panel_actually_set_backlight(dev, 0); > } > @@ -267,6 +270,9 @@ void intel_panel_enable_backlight(struct drm_device *dev) > { > struct drm_i915_private *dev_priv = dev->dev_private; > > + if (!i915_enable_backlight) > + return; > + > if (dev_priv->backlight_level == 0) > dev_priv->backlight_level = intel_panel_get_max_backlight(dev); > > @@ -333,6 +339,9 @@ int intel_panel_setup_backlight(struct drm_device *dev) > struct backlight_properties props; > struct drm_connector *connector; > > + if (!i915_enable_backlight) > + return 0; > + > intel_panel_init_backlight(dev); > > if (dev_priv->int_lvds_connector) > @@ -368,6 +377,9 @@ void intel_panel_destroy_backlight(struct drm_device *dev) > #else > int intel_panel_setup_backlight(struct drm_device *dev) > { > + if (!i915_enable_backlight) > + return; > + > intel_panel_init_backlight(dev); > return 0; > } > -- > 1.7.5.4 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx at lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
