Re: [PATCH v8 1/5] drm/i915: Drop AUX backlight enable check for backlight control

[Puthikorn Voravootivat <puthik@xxxxxxxxxxxx>]

On Wed, May 17, 2017 at 1:09 PM, Pandiyan, Dhinakaran <dhinakaran.pandiyan@xxxxxxxxx> wrote:

________________________________________
From: Puthikorn Voravootivat [puthik@xxxxxxxxxx] on behalf of Puthikorn Voravootivat [puthik@xxxxxxxxxxxx]
Sent: Tuesday, May 16, 2017 5:33 PM
To: intel-gfx@lists.freedesktop.org; Pandiyan, Dhinakaran
Cc: dri-devel@lists.freedesktop.org; Jani Nikula; Navare, Manasi D; Stephane Marchesin; Puthikorn Voravootivat
Subject: [PATCH v8 1/5] drm/i915: Drop AUX backlight enable check for backlight control

There are some panel that
(1) does not support display backlight enable via AUX
(2) support display backlight adjustment via AUX
(3) support display backlight enable via eDP BL_ENABLE pin

The current driver required that (1) must be support to enable (2).
This patch drops that requirement.

Signed-off-by: Puthikorn Voravootivat <puthik@xxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp_aux_backlight.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
index b87c5a381d6a..d32c06583e0b 100644
--- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
@@ -165,7 +165,6 @@ intel_dp_aux_display_control_capable(struct intel_connector *connector)
* the panel can support backlight control over the aux channel
*/
if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
- (intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
!((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_PIN_ENABLE_CAP) ||
(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))) {
--
2.13.0.303.g4ebf302169-goog

^ still has the problem I mentioned last time. How about this?


diff --git a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
index b87c5a3..7072bcf 100644
--- a/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/intel_dp_aux_backlight.c
@@ -28,6 +28,10 @@ static void set_aux_backlight_enable(struct intel_dp *intel_dp, bool enable)
 {
        uint8_t reg_val = 0;

+       /* Early return when display use other mechanism to enable backlight. */
+       if (!(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP))
+               return;
+
        if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_DISPLAY_CONTROL_REGISTER,
                              &reg_val) < 0) {
                DRM_DEBUG_KMS("Failed to read DPCD register 0x%x\n",
@@ -165,10 +169,8 @@ intel_dp_aux_display_control_capable(struct intel_connector *connector)
         * the panel can support backlight control over the aux channel
         */
        if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
-           (intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
            (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
-           !((intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_PIN_ENABLE_CAP) ||
-             (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP))) {
+           !(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) {
                DRM_DEBUG_KMS("AUX Backlight Control Supported!\n");
                return true;
        }

This works too. I probably misunderstood your comment as I move the code to next patch in the set.

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