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. > > > -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 > -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel