| Message ID | 20210208233902.1289693-9-lyude@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: Extract DPCD backlight helpers from i915, add support in nouveau | expand |
On Mon, Feb 08, 2021 at 06:38:58PM -0500, Lyude Paul wrote: > If we can't read DP_EDP_PWMGEN_BIT_COUNT in > intel_dp_aux_vesa_calc_max_backlight() but do have a valid PWM frequency > defined in the VBT, we'll keep going in the function until we inevitably > fail on reading DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN. There's not much point in > doing this, so just return early. > > Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> > --- > drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > 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 611eb3a7cc08..a139f0e08839 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > @@ -449,11 +449,14 @@ static u32 intel_dp_aux_vesa_calc_max_backlight(struct intel_connector *connecto > int freq, fxp, fxp_min, fxp_max, fxp_actual, f = 1; > u8 pn, pn_min, pn_max; > > - if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, &pn) == 1) { > - pn &= DP_EDP_PWMGEN_BIT_COUNT_MASK; > - max_backlight = (1 << pn) - 1; > + if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, &pn) != 1) { > + drm_dbg_kms(&i915->drm, "Failed to read pwmgen bit count cap\n"); > + return 0; > } > > + pn &= DP_EDP_PWMGEN_BIT_COUNT_MASK; > + max_backlight = (1 << pn) - 1; > + > /* Find desired value of (F x P) > * Note that, if F x P is out of supported range, the maximum value or > * minimum value will applied automatically. So no need to check that. > -- > 2.29.2 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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 611eb3a7cc08..a139f0e08839 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c @@ -449,11 +449,14 @@ static u32 intel_dp_aux_vesa_calc_max_backlight(struct intel_connector *connecto int freq, fxp, fxp_min, fxp_max, fxp_actual, f = 1; u8 pn, pn_min, pn_max; - if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, &pn) == 1) { - pn &= DP_EDP_PWMGEN_BIT_COUNT_MASK; - max_backlight = (1 << pn) - 1; + if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, &pn) != 1) { + drm_dbg_kms(&i915->drm, "Failed to read pwmgen bit count cap\n"); + return 0; } + pn &= DP_EDP_PWMGEN_BIT_COUNT_MASK; + max_backlight = (1 << pn) - 1; + /* Find desired value of (F x P) * Note that, if F x P is out of supported range, the maximum value or * minimum value will applied automatically. So no need to check that.
If we can't read DP_EDP_PWMGEN_BIT_COUNT in intel_dp_aux_vesa_calc_max_backlight() but do have a valid PWM frequency defined in the VBT, we'll keep going in the function until we inevitably fail on reading DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN. There's not much point in doing this, so just return early. Signed-off-by: Lyude Paul <lyude@redhat.com> --- drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)