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drm/i915: Correctly enable backlight brightness adjustment via DPCD

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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>
Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170511230225.142870-3-puthik@chromium.org
This commit is contained in:
Puthikorn Voravootivat 2017-05-11 16:02:18 -07:00 committed by Jani Nikula
parent a644ca9bcd
commit 73ab484c90
1 changed files with 27 additions and 6 deletions
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33
drivers/gpu/drm/i915/intel_dp_aux_backlight.c
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@ -97,15 +97,36 @@ 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) != 1) {
DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
DP_EDP_BACKLIGHT_MODE_SET_REGISTER);
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;
if (drm_dp_dpcd_writeb(&intel_dp->aux,
DP_EDP_BACKLIGHT_MODE_SET_REGISTER, dpcd_buf) < 0) {
DRM_DEBUG_KMS("Failed to write aux backlight mode\n");
}
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)