On Tue, 22 Jun 2021, 10:18 PM, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
>On Tue, 22 Jun 2021, Lee Shawn C <shawn.c.lee@xxxxxxxxx> wrote:
>> This workaround is specific for a particular panel on Google
>> chromebook project. When user space daemon enter idle state.
>> It request adjust brightness to 0, turn backlight_enable signal off
>> and keep eDP main link active.
>>
>> On general LCD, this behavior might not be a problem.
>> But on this panel, its tcon would expect source to execute full eDP
>> power off sequence after drop backlight_enable signal.
>> Without eDP power off sequence. Even source try to turn
>> backlight_enable signal on and restore proper brightness level.
>> This panel is not able to light on again.
>>
>> This WA ignored the request from user space daemon to disable
>> backlight_enable signal and keep it on always. When user space request
>> kernel to turn eDP display off, kernel driver still can control
>> backlight_enable signal properly. It would not impact standard eDP
>> power off sequence.
>>
>> Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
>> Cc: Imre Deak <imre.deak@xxxxxxxxx>
>> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
>> Cc: Cooper Chiou <cooper.chiou@xxxxxxxxx>
>>
>> Signed-off-by: Lee Shawn C <shawn.c.lee@xxxxxxxxx>
>> ---
>> drivers/gpu/drm/i915/display/intel_panel.c | 4 ++-
>> drivers/gpu/drm/i915/display/intel_quirks.c | 34 +++++++++++++++++++++
>> drivers/gpu/drm/i915/i915_drv.h | 1 +
>> 3 files changed, 38 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c
>> b/drivers/gpu/drm/i915/display/intel_panel.c
>> index 7d7a60b4d2de..0212b53d932b 100644
>> --- a/drivers/gpu/drm/i915/display/intel_panel.c
>> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
>> @@ -1311,6 +1311,7 @@ static void intel_panel_set_backlight(const
>> struct drm_connector_state *conn_sta static int
>> intel_backlight_device_update_status(struct backlight_device *bd) {
>> struct intel_connector *connector = bl_get_data(bd);
>> + struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
>> struct intel_panel *panel = &connector->panel;
>> struct drm_device *dev = connector->base.dev;
>>
>> @@ -1330,7 +1331,8 @@ static int intel_backlight_device_update_status(struct backlight_device *bd)
>> if (panel->backlight.power) {
>> bool enable = bd->props.power == FB_BLANK_UNBLANK &&
>> bd->props.brightness != 0;
>> - panel->backlight.power(connector, enable);
>> + if (enable || !(dev_priv->quirks & QUIRK_KEEP_BACKLIGHT_ENABLE_ON))
>> + panel->backlight.power(connector, enable);
>
>We'll want to avoid the hook altogether in this case, instead of complicating the logic even more. Something like:
>
>--- a/drivers/gpu/drm/i915/display/intel_dp.c
>+++ b/drivers/gpu/drm/i915/display/intel_dp.c
>@@ -5286,7 +5286,8 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp,
> }
>
> intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
>- intel_connector->panel.backlight.power = intel_pps_backlight_power;
>+ if (!(dev_priv->quirks & QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK))
>+ intel_connector->panel.backlight.power = intel_pps_backlight_power;
> intel_panel_setup_backlight(connector, pipe);
>
> if (fixed_mode) {
>
>---
>
>Please adjust the quirk name and debug logs accordingly.
>
Thanks! I will modify the quirk name and debug messages later.
>Truth be told I'd rather nuke the hook completely. But it was a request from Chrome to have this lightweight sub-state to black out the display, without mode set, using the panel power sequencer in cases where we can't set the backlight PWM to 0.
>
>Hmm. Is the brightness controlled using PWM or DPCD? We probably shouldn't do this at all when the brightness control is done using DPCD.
This panel refer to soc's backlight_enable signal to enable backlight. But adjust brightness via DPCD aux interface.
If source turn backlight_enable signal off, panel tcon await source execute full eDP power off sequence to disable local display.
And panel's backlight is not able to turn on again.
Best regards,
Shawn
>
>BR,
>Jani.
>
>
>> }
>> } else {
>> bd->props.power = FB_BLANK_POWERDOWN; diff --git
>> a/drivers/gpu/drm/i915/display/intel_quirks.c
>> b/drivers/gpu/drm/i915/display/intel_quirks.c
>> index 98dd787b00e3..ed57b083edbb 100644
>> --- a/drivers/gpu/drm/i915/display/intel_quirks.c
>> +++ b/drivers/gpu/drm/i915/display/intel_quirks.c
>> @@ -53,6 +53,12 @@ static void quirk_increase_ddi_disabled_time(struct drm_i915_private *i915)
>> drm_info(&i915->drm, "Applying Increase DDI Disabled quirk\n"); }
>>
>> +static void quirk_keep_backlight_enable_on(struct drm_i915_private
>> +*i915) {
>> + i915->quirks |= QUIRK_KEEP_BACKLIGHT_ENABLE_ON;
>> + drm_info(&i915->drm, "applying keep backlight enable on quirk\n"); }
>> +
>> struct intel_quirk {
>> int device;
>> int subsystem_vendor;
>> @@ -72,6 +78,12 @@ static int intel_dmi_reverse_brightness(const struct dmi_system_id *id)
>> return 1;
>> }
>>
>> +static int backlight_wa_callback(const struct dmi_system_id *id) {
>> + DRM_INFO("This is WA to ignore backlight off to prevent OLED panel issue on %s device\n", id->ident);
>> + return 1;
>> +}
>> +
>> static const struct intel_dmi_quirk intel_dmi_quirks[] = {
>> {
>> .dmi_id_list = &(const struct dmi_system_id[]) { @@ -96,6 +108,28
>> @@ static const struct intel_dmi_quirk intel_dmi_quirks[] = {
>> },
>> .hook = quirk_invert_brightness,
>> },
>> + {
>> + .dmi_id_list = &(const struct dmi_system_id[]) {
>> + {
>> + .callback = backlight_wa_callback,
>> + .ident = "Google Lillipup",
>> + .matches = {DMI_MATCH(DMI_BOARD_VENDOR, "Google"),
>> + DMI_MATCH(DMI_BOARD_NAME, "Lindar"),
>> + DMI_MATCH(DMI_PRODUCT_SKU, "sku524294"),
>> + },
>> + },
>> + {
>> + .callback = backlight_wa_callback,
>> + .ident = "Google Lillipup",
>> + .matches = {DMI_MATCH(DMI_BOARD_VENDOR, "Google"),
>> + DMI_MATCH(DMI_BOARD_NAME, "Lindar"),
>> + DMI_MATCH(DMI_PRODUCT_SKU, "sku524295"),
>> + },
>> + },
>> + { }
>> + },
>> + .hook = quirk_keep_backlight_enable_on,
>> + },
>> };
>>
>> static struct intel_quirk intel_quirks[] = { diff --git
>> a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index 01e11fe38642..8103919bf3b4 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -467,6 +467,7 @@ struct i915_drrs { #define
>> QUIRK_PIN_SWIZZLED_PAGES (1<<5) #define QUIRK_INCREASE_T12_DELAY
>> (1<<6) #define QUIRK_INCREASE_DDI_DISABLED_TIME (1<<7)
>> +#define QUIRK_KEEP_BACKLIGHT_ENABLE_ON (1<<8)
>>
>> struct intel_fbdev;
>> struct intel_fbc_work;
>
>--
>Jani Nikula, Intel Open Source Graphics Center
>
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