On Wed, 2017-05-10 at 13:05 +0300, Jani Nikula wrote: > On Wed, 10 May 2017, "Pandiyan, Dhinakaran" <dhinakaran.pandiyan@xxxxxxxxx> wrote: > > On Tue, 2017-05-09 at 16:39 -0700, Puthikorn Voravootivat wrote: > >> > How is backlight enabled in this case? > >> Using eDP BL_ENABLE pin > > > > > > Sure, but I am not seeing how this falls back to one of the > > [bxt,lpt]_enable_backlight() functions in intel_panel.c. Apologies if I > > am missing something very obvious. > > > > If intel_dp_aux_init_backlight_funcs() returned -ENODEV, then one of the > > platform specific PWM enable callbacks would be called. But in this > > case, dp_aux_enable_backlight() just returns without doing anything. > > The eDP BL_ENABLE pin (in the physical eDP connector) is controlled by > the panel power sequencer, independent from the PWM control. See > intel_edp_backlight_* functions in intel_dp.c. > > BR, > Jani. > > Ah! Thanks, that makes sense. The naming is a bit confusing though. The _enable_backlight() functions in intel_panel.c don't enable backlight but enable PWM. > > > > > > -DK > >> > >> > >> On Sat, May 6, 2017 at 1:59 AM, Pandiyan, Dhinakaran > >> <dhinakaran.pandiyan@xxxxxxxxx> wrote: > >> On Wed, 2017-05-03 at 17:28 -0700, Puthikorn Voravootivat > >> wrote: > >> > There are some panel that > >> > (1) does not support display backlight enable via AUX > >> > (2) support display backlight adjustment via AUX > >> > (3) support display backlight enable via eDP BL_ENABLE pin > >> > > >> > The current driver required that (1) must be support to > >> enable (2). > >> > This patch drops that requirement. > >> > > >> > Signed-off-by: Puthikorn Voravootivat <puthik@xxxxxxxxxxxx> > >> > --- > >> > drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 5 ++++- > >> > 1 file changed, 4 insertions(+), 1 deletion(-) > >> > > >> > diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > >> b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > >> > index ad8560c5f689..5b83c9737644 100644 > >> > --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > >> > +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > >> > @@ -28,6 +28,10 @@ static void > >> set_aux_backlight_enable(struct intel_dp *intel_dp, bool > >> enable) > >> > { > >> > uint8_t reg_val = 0; > >> > > >> > + /* Early return when display use other mechanism to > >> enable backlight. */ > >> > + if (!(intel_dp->edp_dpcd[1] & > >> DP_EDP_BACKLIGHT_AUX_ENABLE_CAP)) > >> > + return; > >> > + > >> > >> How is backlight enabled in this case? > >> > >> -DK > >> > >> > if (drm_dp_dpcd_readb(&intel_dp->aux, > >> DP_EDP_DISPLAY_CONTROL_REGISTER, > >> > ®_val) < 0) { > >> > DRM_DEBUG_KMS("Failed to read DPCD register 0x > >> %x\n", > >> > @@ -164,7 +168,6 @@ > >> intel_dp_aux_display_control_capable(struct intel_connector > >> *connector) > >> > * the panel can support backlight control over the > >> aux channel > >> > */ > >> > if ((intel_dp->edp_dpcd[1] & > >> DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP) && > >> > - (intel_dp->edp_dpcd[1] & > >> DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) && > >> > (intel_dp->edp_dpcd[2] & > >> DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) { > >> > DRM_DEBUG_KMS("AUX Backlight Control > >> Supported!\n"); > >> > return true; > >> > >> > >> > >> > >> _______________________________________________ > >> Intel-gfx mailing list > >> Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > >> https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel