On Mon, Jun 09, 2014 at 06:24:34PM +0300, Jani Nikula wrote: > For reasons I can't claim to fully understand gen4 seems to require > backlight duty cycle setting after the backlight has been enabled, or > else black screen follows. I don't have documentation for the correct > sequence on gen4 either. Confirmed on Dell Latitude D630 and MacBook4,1. > > This fixes a regression introduced by > commit b35684b8fa94e04f55fd38bf672b737741d2f9e2 > Author: Jani Nikula <jani.nikula@xxxxxxxxx> > Date: Thu Nov 14 12:13:41 2013 +0200 > > drm/i915: do full backlight setup at enable time > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=75791 > Reported-and-tested-by: mcy@xxxxxx > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79423 > Reported-and-tested-by: Marc Milgram <mmilgram@xxxxxxxxxx> > Cc: Stable <stable@xxxxxxxxxxxxxxx> # 3.14+ > Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Yeah, docs don't mention anything. But if it works it's fine, so Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx> > --- > drivers/gpu/drm/i915/intel_panel.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c > index 5e6c888b4928..38a98570d10c 100644 > --- a/drivers/gpu/drm/i915/intel_panel.c > +++ b/drivers/gpu/drm/i915/intel_panel.c > @@ -798,9 +798,6 @@ static void i965_enable_backlight(struct intel_connector *connector) > ctl = freq << 16; > I915_WRITE(BLC_PWM_CTL, ctl); > > - /* XXX: combine this into above write? */ > - intel_panel_actually_set_backlight(connector, panel->backlight.level); > - > ctl2 = BLM_PIPE(pipe); > if (panel->backlight.combination_mode) > ctl2 |= BLM_COMBINATION_MODE; > @@ -809,6 +806,8 @@ static void i965_enable_backlight(struct intel_connector *connector) > I915_WRITE(BLC_PWM_CTL2, ctl2); > POSTING_READ(BLC_PWM_CTL2); > I915_WRITE(BLC_PWM_CTL2, ctl2 | BLM_PWM_ENABLE); > + > + intel_panel_actually_set_backlight(connector, panel->backlight.level); > } > > static void vlv_enable_backlight(struct intel_connector *connector) > -- > 1.9.1 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html