On Thu, 19 Nov 2015, Jani Nikula <jani.nikula@xxxxxxxxx> wrote: > This reverts > > commit 6764e9f8724f1231b4deac53b9a82286ac0830e7 > Author: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> > Date: Thu Aug 27 15:44:06 2015 +0200 > > drm/i915: skip modeset if compatible for everyone. > > Bring back the i915.fastboot module parameter, disabled by default, due > to backlight regression on Chromebook Pixel 2015. > > Apparently the firmware of the Chromebook in question enables the panel > but disables backlight to avoid a brief garbage scanout upon loading the > kernel/module. With fastboot, we leave the backlight untouched, in this > case disabled. The user would have to do a modeset (i.e. not just crank > up the brightness) to enable the backlight. > > There is no clean fix readily available, so get back to the drawing > board by reverting. > > [N.B. The reference below is for when the thread was included on public > lists, and some of the context had already been dropped by then.] > > Reported-and-tested-by: Olof Johansson <olof@xxxxxxxxx> > Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx> > References: http://marc.info/?i=CAKMK7uES7xk05ki92oeX6gmvZWAh9f2vL7yz=6T+fGK9J3X7cQ@xxxxxxxxxxxxxx > Fixes: 6764e9f8724f ("drm/i915: skip modeset if compatible for everyone.") > Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Pushed to drm-intel-fixes with IRC acks from Daniel and Maarten (*). I took the liberty of adding Tested-by from Olof, as he reported reverting the bad commit fixes the issue for him, and it's a clean revert. BR, Jani. (*) In truth Maarten said "sigh", I presumed short for Sighed-off-by, which I took to be close enough to Acked-by. > --- > drivers/gpu/drm/i915/i915_drv.h | 1 + > drivers/gpu/drm/i915/i915_params.c | 5 +++++ > drivers/gpu/drm/i915/intel_display.c | 3 ++- > 3 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h > index 6db4e76dc7eb..a47e0f4fab56 100644 > --- a/drivers/gpu/drm/i915/i915_drv.h > +++ b/drivers/gpu/drm/i915/i915_drv.h > @@ -2656,6 +2656,7 @@ struct i915_params { > int enable_cmd_parser; > /* leave bools at the end to not create holes */ > bool enable_hangcheck; > + bool fastboot; > bool prefault_disable; > bool load_detect_test; > bool reset; > diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c > index 0f5af02e90e9..835d6099c769 100644 > --- a/drivers/gpu/drm/i915/i915_params.c > +++ b/drivers/gpu/drm/i915/i915_params.c > @@ -41,6 +41,7 @@ struct i915_params i915 __read_mostly = { > .preliminary_hw_support = IS_ENABLED(CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT), > .disable_power_well = -1, > .enable_ips = 1, > + .fastboot = 0, > .prefault_disable = 0, > .load_detect_test = 0, > .reset = true, > @@ -139,6 +140,10 @@ MODULE_PARM_DESC(disable_power_well, > module_param_named_unsafe(enable_ips, i915.enable_ips, int, 0600); > MODULE_PARM_DESC(enable_ips, "Enable IPS (default: true)"); > > +module_param_named(fastboot, i915.fastboot, bool, 0600); > +MODULE_PARM_DESC(fastboot, > + "Try to skip unnecessary mode sets at boot time (default: false)"); > + > module_param_named_unsafe(prefault_disable, i915.prefault_disable, bool, 0600); > MODULE_PARM_DESC(prefault_disable, > "Disable page prefaulting for pread/pwrite/reloc (default:false). " > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c > index 9a1c1d48a7d8..46015af47c20 100644 > --- a/drivers/gpu/drm/i915/intel_display.c > +++ b/drivers/gpu/drm/i915/intel_display.c > @@ -13236,7 +13236,8 @@ static int intel_atomic_check(struct drm_device *dev, > if (ret) > return ret; > > - if (intel_pipe_config_compare(state->dev, > + if (i915.fastboot && > + intel_pipe_config_compare(state->dev, > to_intel_crtc_state(crtc->state), > pipe_config, true)) { > crtc_state->mode_changed = false; -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
