diff options
| author | Lyude Paul <lyude@redhat.com> | 2021-05-14 14:15:00 -0400 |
|---|---|---|
| committer | Lyude Paul <lyude@redhat.com> | 2021-06-09 13:35:21 -0400 |
| commit | 17917ff62443414569ea76e151e7a7ef44812264 (patch) | |
| tree | 31e1a98cc49f3d9cf9ec23f2291659f44473d341 /drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | |
| parent | ade673bb2ba496a66250c5c2006c502c3d734ea2 (diff) | |
drm/i915/dpcd_bl: Return early in vesa_calc_max_backlight if we can't read PWMGEN_BIT_COUNT
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>
Link: https://patchwork.freedesktop.org/patch/msgid/20210514181504.565252-7-lyude@redhat.com
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 9 |
1 files 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 781c7cd98d75..bf8e4ed56847 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. |