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.
>
> v2: modify the quirk name and debug messages.
> unregister backlight.power callback for specific device.
>
> 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_dp.c | 3 +-
> drivers/gpu/drm/i915/display/intel_quirks.c | 34 +++++++++++++++++++++
> drivers/gpu/drm/i915/i915_drv.h | 1 +
> 3 files changed, 37 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 6cc03b9e4321..d3312b9bcc6f 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5238,7 +5238,8 @@ 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) {
> diff --git a/drivers/gpu/drm/i915/display/intel_quirks.c b/drivers/gpu/drm/i915/display/intel_quirks.c
> index 98dd787b00e3..5f3cb006db01 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_no_pps_backlight_power_hook(struct drm_i915_private *i915)
> +{
> + i915->quirks |= QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK;
> + drm_info(&i915->drm, "Applying no pps backlight power 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 intel_dmi_no_pps_backlight(const struct dmi_system_id *id)
> +{
> + DRM_INFO("This workaround prevented panel backlight issue on %s device\n", id->ident);
Not sure I like the verbose "This workaround ..." style messages.
Contrast with what the messages for reverse polarity would be via dmi:
"Backlight polarity reversed on %s\n"
->
"applying inverted panel brightness quirk\n"
> + 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 = intel_dmi_no_pps_backlight,
> + .ident = "Google Lillipup",
> + .matches = {DMI_MATCH(DMI_BOARD_VENDOR, "Google"),
> + DMI_MATCH(DMI_BOARD_NAME, "Lindar"),
> + DMI_MATCH(DMI_PRODUCT_SKU, "sku524294"),
> + },
> + },
> + {
> + .callback = intel_dmi_no_pps_backlight,
> + .ident = "Google Lillipup",
> + .matches = {DMI_MATCH(DMI_BOARD_VENDOR, "Google"),
> + DMI_MATCH(DMI_BOARD_NAME, "Lindar"),
> + DMI_MATCH(DMI_PRODUCT_SKU, "sku524295"),
> + },
I think you should use DMI_EXACT_MATCH instead of DMI_MATCH. The former
users strcmp while the latter uses strstr for comparison.
The .ident string should probably be different for the two cases;
otherwise the DRM_INFO() logging above does not differentiate between
the two.
Sorry for not catching all of these at v1 review. Anyway, this is just
small details, the approach is fine.
BR,
Jani.
> + },
> + { }
> + },
> + .hook = quirk_no_pps_backlight_power_hook,
> + },
> };
>
> 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..5a065be0792a 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_NO_PPS_BACKLIGHT_POWER_HOOK (1<<8)
>
> struct intel_fbdev;
> struct intel_fbc_work;
--
Jani Nikula, Intel Open Source Graphics Center
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
