From: Lyude Paul <lyude@redhat.com> To: Jani Nikula <jani.nikula@linux.intel.com>, Vasily Khoruzhick <anarsoul@gmail.com>, Joonas Lahtinen <joonas.lahtinen@linux.intel.com>, Rodrigo Vivi <rodrigo.vivi@intel.com>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Sean Paul <seanpaul@chromium.org>, Aaron Ma <aaron.ma@canonical.com>, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH] drm/i915/dp: add a delay before setting panel brightness after power on Date: Tue, 14 Sep 2021 17:08:32 -0400 [thread overview] Message-ID: <410de2c8e865446ec7f9d72a419b2674d34891bf.camel@redhat.com> (raw) In-Reply-To: <87r1dr34nk.fsf@intel.com> On Tue, 2021-09-14 at 12:09 +0300, Jani Nikula wrote: > On Mon, 13 Sep 2021, Vasily Khoruzhick <anarsoul@gmail.com> wrote: > > Panel in my Dell XPS 7590, that uses Intel's HDR backlight interface to > > control brightness, apparently needs a delay before setting brightness > > after power on. Without this delay the panel does accept the setting > > and may come up with some arbitrary brightness (sometimes it's too dark, > > sometimes it's too bright, I wasn't able to find a system). > > > > I don't have access to the spec, so I'm not sure if it's expected > > behavior or a quirk for particular device. > > > > Delay was chosen by experiment: it works with 100ms, but fails with > > anything lower than 75ms. > > Looks like we don't respect the panel delays for DPCD backlight. The > values are used for setting up the panel power sequencer, and thus PWM > based backlight, but we should probably use the delays in DPCD backlight > code too. This makes sense to me, you're referring to the panel delays in the VBT correct? > > BR, > Jani. > > > > > > Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com> > > --- > > drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > > b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > > index 4f8337c7fd2e..c4f35e1b5870 100644 > > --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > > @@ -210,6 +210,10 @@ intel_dp_aux_hdr_enable_backlight(const struct > > intel_crtc_state *crtc_state, > > > > ctrl = old_ctrl; > > if (panel->backlight.edp.intel.sdr_uses_aux) { > > + /* Wait 100ms to ensure that panel is ready otherwise it > > may not > > + * set chosen backlight level > > + */ > > + msleep(100); > > ctrl |= INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE; > > intel_dp_aux_hdr_set_aux_backlight(conn_state, level); > > } else { > -- Cheers, Lyude Paul (she/her) Software Engineer at Red Hat
WARNING: multiple messages have this Message-ID (diff)
From: Lyude Paul <lyude@redhat.com> To: Jani Nikula <jani.nikula@linux.intel.com>, Vasily Khoruzhick <anarsoul@gmail.com>, Joonas Lahtinen <joonas.lahtinen@linux.intel.com>, Rodrigo Vivi <rodrigo.vivi@intel.com>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Sean Paul <seanpaul@chromium.org>, Aaron Ma <aaron.ma@canonical.com>, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: Re: [Intel-gfx] [PATCH] drm/i915/dp: add a delay before setting panel brightness after power on Date: Tue, 14 Sep 2021 17:08:32 -0400 [thread overview] Message-ID: <410de2c8e865446ec7f9d72a419b2674d34891bf.camel@redhat.com> (raw) In-Reply-To: <87r1dr34nk.fsf@intel.com> On Tue, 2021-09-14 at 12:09 +0300, Jani Nikula wrote: > On Mon, 13 Sep 2021, Vasily Khoruzhick <anarsoul@gmail.com> wrote: > > Panel in my Dell XPS 7590, that uses Intel's HDR backlight interface to > > control brightness, apparently needs a delay before setting brightness > > after power on. Without this delay the panel does accept the setting > > and may come up with some arbitrary brightness (sometimes it's too dark, > > sometimes it's too bright, I wasn't able to find a system). > > > > I don't have access to the spec, so I'm not sure if it's expected > > behavior or a quirk for particular device. > > > > Delay was chosen by experiment: it works with 100ms, but fails with > > anything lower than 75ms. > > Looks like we don't respect the panel delays for DPCD backlight. The > values are used for setting up the panel power sequencer, and thus PWM > based backlight, but we should probably use the delays in DPCD backlight > code too. This makes sense to me, you're referring to the panel delays in the VBT correct? > > BR, > Jani. > > > > > > Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com> > > --- > > drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > > b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > > index 4f8337c7fd2e..c4f35e1b5870 100644 > > --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > > @@ -210,6 +210,10 @@ intel_dp_aux_hdr_enable_backlight(const struct > > intel_crtc_state *crtc_state, > > > > ctrl = old_ctrl; > > if (panel->backlight.edp.intel.sdr_uses_aux) { > > + /* Wait 100ms to ensure that panel is ready otherwise it > > may not > > + * set chosen backlight level > > + */ > > + msleep(100); > > ctrl |= INTEL_EDP_HDR_TCON_BRIGHTNESS_AUX_ENABLE; > > intel_dp_aux_hdr_set_aux_backlight(conn_state, level); > > } else { > -- Cheers, Lyude Paul (she/her) Software Engineer at Red Hat
next prev parent reply other threads:[~2021-09-14 21:08 UTC|newest] Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-13 19:35 [PATCH] drm/i915/dp: add a delay before setting panel brightness after power on Vasily Khoruzhick 2021-09-13 19:35 ` [Intel-gfx] " Vasily Khoruzhick 2021-09-13 22:34 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork 2021-09-14 1:58 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork 2021-09-14 9:09 ` [PATCH] " Jani Nikula 2021-09-14 9:09 ` [Intel-gfx] " Jani Nikula 2021-09-14 21:08 ` Lyude Paul [this message] 2021-09-14 21:08 ` Lyude Paul 2021-09-14 22:31 ` Jani Nikula 2021-09-14 22:31 ` [Intel-gfx] " Jani Nikula 2021-09-15 1:10 ` Vasily Khoruzhick 2021-09-15 1:10 ` [Intel-gfx] " Vasily Khoruzhick 2021-09-15 8:47 ` Jani Nikula 2021-09-15 8:47 ` [Intel-gfx] " Jani Nikula 2021-09-20 6:57 ` Vasily Khoruzhick 2021-09-20 6:57 ` [Intel-gfx] " Vasily Khoruzhick
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