[Intel-gfx] [PATCH] drm/i915: set backlight duty cycle after backlight enable for gen4
Daniel Vetter
daniel at ffwll.ch
Tue Jun 10 09:25:36 CEST 2014
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 at intel.com>
> 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 at lm7.fr
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79423
> Reported-and-tested-by: Marc Milgram <mmilgram at redhat.com>
> Cc: Stable <stable at vger.kernel.org> # 3.14+
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
Yeah, docs don't mention anything. But if it works it's fine, so
Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
> 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
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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