| Message ID | 20170308213053.194062-3-puthik@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 08 Mar 2017, Puthikorn Voravootivat <puthik@chromium.org> wrote: > intel_dp_aux_enable_backlight() assumed that the register > BACKLIGHT_BRIGHTNESS_CONTROL_MODE can only has value 01 > (DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET) when initialize. > > This patch fixed that by handling all cases of that register. > > Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org> > --- > drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 29 +++++++++++++++++++++------ > 1 file changed, 23 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > index abfb09c1269f..16cd1265d264 100644 > --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c > @@ -101,15 +101,32 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector) > { > struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base); > uint8_t dpcd_buf = 0; > + uint8_t edp_backlight_mode = 0; > > set_aux_backlight_enable(intel_dp, true); > > - if ((drm_dp_dpcd_readb(&intel_dp->aux, > - DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) == 1) && > - ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) == > - DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET)) > - drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, > - (dpcd_buf | DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD)); That's clearly bonkers, it ends up selecting DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT by accident, not DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD, because it doesn't mask the bits. > + if (!drm_dp_dpcd_readb(&intel_dp->aux, > + DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf)) { > + return; > + } > + > + edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; > + > + switch (edp_backlight_mode) { > + case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM: > + case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET: > + dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; > + dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD; > + drm_dp_dpcd_writeb(&intel_dp->aux, > + DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf); > + break; > + > + /* Do nothing in these cases */ > + case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD: > + case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT: Based on the current requirements for using DPCD backlight control, the only power-on default we should end up here with is DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET. In particular, I don't think we should accept the PRODUCT mode without ensuring we output PWM to the eDP pins as well. And currently DPCD and PWM controls are mutually exclusive. BR, Jani. > + default: > + break; > + } > } > > static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c index abfb09c1269f..16cd1265d264 100644 --- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c +++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c @@ -101,15 +101,32 @@ static void intel_dp_aux_enable_backlight(struct intel_connector *connector) { struct intel_dp *intel_dp = enc_to_intel_dp(&connector->encoder->base); uint8_t dpcd_buf = 0; + uint8_t edp_backlight_mode = 0; set_aux_backlight_enable(intel_dp, true); - if ((drm_dp_dpcd_readb(&intel_dp->aux, - DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf) == 1) && - ((dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK) == - DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET)) - drm_dp_dpcd_writeb(&intel_dp->aux, DP_EDP_BACKLIGHT_MODE_SET_REGISTER, - (dpcd_buf | DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD)); + if (!drm_dp_dpcd_readb(&intel_dp->aux, + DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf)) { + return; + } + + edp_backlight_mode = dpcd_buf & DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; + + switch (edp_backlight_mode) { + case DP_EDP_BACKLIGHT_CONTROL_MODE_PWM: + case DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET: + dpcd_buf &= ~DP_EDP_BACKLIGHT_CONTROL_MODE_MASK; + dpcd_buf |= DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD; + drm_dp_dpcd_writeb(&intel_dp->aux, + DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf); + break; + + /* Do nothing in these cases */ + case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD: + case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT: + default: + break; + } } static void intel_dp_aux_disable_backlight(struct intel_connector *connector)
intel_dp_aux_enable_backlight() assumed that the register BACKLIGHT_BRIGHTNESS_CONTROL_MODE can only has value 01 (DP_EDP_BACKLIGHT_CONTROL_MODE_PRESET) when initialize. This patch fixed that by handling all cases of that register. Signed-off-by: Puthikorn Voravootivat <puthik@chromium.org> --- drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 29 +++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-)