On Tue, 18 Apr 2017, Puthikorn Voravootivat <[email protected]> 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.
Fixes like this should precede the functional changes, i.e. this should be earlier in the series. > > Signed-off-by: Puthikorn Voravootivat <[email protected]> > --- > 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 42f73d9a3ccf..f06c8381c74e 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)); Ugh, that's really totally busted, since this actually enables the product mode because it doesn't mask out the preset first. Thanks for fixing this. > + if (!drm_dp_dpcd_readb(&intel_dp->aux, > + DP_EDP_BACKLIGHT_MODE_SET_REGISTER, &dpcd_buf)) { I don't think there are any valid scenarious where this call would return 0. if (... != 1) is the right check. > + 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: > + case DP_EDP_BACKLIGHT_CONTROL_MODE_PRODUCT: > + 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); I wonder if the right order would be to set the mode first, and call set_aux_backlight_enable() after that. I couldn't find anything about that in the spec, but gut feeling says that would be better. Needs to be a separate change though. BR, Jani. > + break; > + > + /* Do nothing when it is already DPCD mode */ > + case DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD: > + default: > + break; > + } > } > > static void intel_dp_aux_disable_backlight(struct intel_connector *connector) -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
