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

[Pandiyan, Dhinakaran]

On Wed, 2017-05-17 at 14:04 -0700, Puthikorn Voravootivat wrote:
> 
> On Wed, May 17, 2017 at 1:09 PM, Pandiyan, Dhinakaran
> <dhinakaran.pandiyan at intel.com> wrote:
>         
>         ________________________________________
>         From: Puthikorn Voravootivat [puthik at google.com] on behalf of
>         Puthikorn Voravootivat [puthik at chromium.org]
>         Sent: Tuesday, May 16, 2017 5:33 PM
>         To: intel-gfx at lists.freedesktop.org; Pandiyan, Dhinakaran
>         Cc: dri-devel at 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 at chromium.org>
>         ---
>         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.


Please feel free to question any of the comments if you do not agree.

-DK

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