On Tue, 08 Jan 2019, Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> wrote: > On lynxpoint the bios sometimes sets up the backlight using the CPU > display, but the driver expects using the PWM PCH override register. > > Read the value from the CPU register, then convert it to the other > units by converting from the old duty cycle, to freq, to the new units. > > This value is then programmed in the override register, after which > we set the override and disable the CPU display control. This allows > us to switch the source without flickering, and make the backlight > controls work in the driver. > > Changes since v1: > - Read BLC_PWM_CPU_CTL2 to cpu_ctl2. > - Clean up cpu_mode if slightly. > - Always disable BLM_PWM_ENABLE in cpu_ctl2. > Changes since v2: > - Simplify cpu_mode handling (Jani) > > Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108225 > Cc: Basil Eric Rabi <ericbasil.rabi@xxxxxxxxx> > Cc: Hans de Goede <jwrdegoede@xxxxxxxxxxxxxxxxx> > Cc: Tolga Cakir <cevelnet@xxxxxxxxx> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Tested-by: Tolga Cakir <cevelnet@xxxxxxxxx> > Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_panel.c | 26 ++++++++++++++++++++++---- > 1 file changed, 22 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c > index f71b33cf1c97..1c9ef54d58fe 100644 > --- a/drivers/gpu/drm/i915/intel_panel.c > +++ b/drivers/gpu/drm/i915/intel_panel.c > @@ -1493,8 +1493,8 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus > { > struct drm_i915_private *dev_priv = to_i915(connector->base.dev); > struct intel_panel *panel = &connector->panel; > - u32 pch_ctl1, pch_ctl2, val; > - bool alt; > + u32 cpu_ctl2, pch_ctl1, pch_ctl2, val; > + bool alt, cpu_mode; > > if (HAS_PCH_LPT(dev_priv)) > alt = I915_READ(SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY; > @@ -1508,6 +1508,8 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus > pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2); > panel->backlight.max = pch_ctl2 >> 16; > > + cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2); > + > if (!panel->backlight.max) > panel->backlight.max = get_backlight_max_vbt(connector); > > @@ -1516,12 +1518,28 @@ static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unus > > panel->backlight.min = get_backlight_min_vbt(connector); > > - val = lpt_get_backlight(connector); > + panel->backlight.enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE; > + > + cpu_mode = panel->backlight.enabled && HAS_PCH_LPT(dev_priv) && > + !(pch_ctl1 & BLM_PCH_OVERRIDE_ENABLE) && > + (cpu_ctl2 & BLM_PWM_ENABLE); > + if (cpu_mode) > + val = pch_get_backlight(connector); > + else > + val = lpt_get_backlight(connector); > val = intel_panel_compute_brightness(connector, val); > panel->backlight.level = clamp(val, panel->backlight.min, > panel->backlight.max); > > - panel->backlight.enabled = pch_ctl1 & BLM_PCH_PWM_ENABLE; > + if (cpu_mode) { > + DRM_DEBUG_KMS("CPU backlight register was enabled, switching to PCH override\n"); > + > + /* Write converted CPU PWM value to PCH override register */ > + lpt_set_backlight(connector->base.state, panel->backlight.level); > + I915_WRITE(BLC_PWM_PCH_CTL1, pch_ctl1 | BLM_PCH_OVERRIDE_ENABLE); > + > + I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2 & ~BLM_PWM_ENABLE); > + } > > return 0; > } -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
