Re: [RFC PATCH 1/1] drm/i915/display: Avoid unsupported 300Hz output mode on a TUXEDO device

["Murthy, Arun R" <arun.r.murthy@intel.com>]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Werner
> Sembach
> Sent: Saturday, July 5, 2025 12:34 AM
> To: Jani Nikula <jani.nikula@linux.intel.com>; Vivi, Rodrigo
> <rodrigo.vivi@intel.com>; Joonas Lahtinen <joonas.lahtinen@linux.intel.com>;
> Tvrtko Ursulin <tursulin@ursulin.net>; David Airlie <airlied@gmail.com>;
> Simona Vetter <simona@ffwll.ch>
> Cc: Tim Guttzeit <t.guttzeit@tuxedocomputers.com>; Werner Sembach
> <wse@tuxedocomputers.com>; intel-gfx@lists.freedesktop.org; intel-
> xe@lists.freedesktop.org; dri-devel@lists.freedesktop.org; linux-
> kernel@vger.kernel.org
> Subject: [RFC PATCH 1/1] drm/i915/display: Avoid unsupported 300Hz output
> mode on a TUXEDO device
> 
> From: Tim Guttzeit <t.guttzeit@tuxedocomputers.com>
> 
> Removes all display modes with more than 240 Hz for the integrated display on
> a TUXEDO Stellaris 16 Gen7, because using the iGPU with higer refresh rates
> causes screen flicker.
> 
> Signed-off-by: Tim Guttzeit <t.guttzeit@tuxedocomputers.com>
> Co-developed-by: Werner Sembach <wse@tuxedocomputers.com>
> Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c     |  5 ++++
>  drivers/gpu/drm/i915/display/intel_quirks.c | 30 +++++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_quirks.h |  1 +
>  3 files changed, 36 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 640c43bf62d4c..5ce00cfe36ee1 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1436,6 +1436,11 @@ intel_dp_mode_valid(struct drm_connector
> *_connector,
>  	if (mode->clock < 10000)
>  		return MODE_CLOCK_LOW;
> 
> +	if (intel_has_quirk(display, QUIRK_EDP_MAX_240HZ_HOOK) &&
> +	    intel_dp_is_edp(intel_dp) &&
> +	    drm_mode_vrefresh(mode) > 240)
> +		return MODE_BAD;
> +
Adding a quirk for this is not the right approach. If this is not 
supported by the display, should have been pruned by the driver.

Thanks and Regards,
Arun R Murthy
------------->  	fixed_mode = intel_panel_fixed_mode(connector, mode);
>  	if (intel_dp_is_edp(intel_dp) && fixed_mode) {
>  		status = intel_panel_mode_valid(connector, mode); diff --git
> a/drivers/gpu/drm/i915/display/intel_quirks.c
> b/drivers/gpu/drm/i915/display/intel_quirks.c
> index a32fae510ed27..438ce2cb37a01 100644
> --- a/drivers/gpu/drm/i915/display/intel_quirks.c
> +++ b/drivers/gpu/drm/i915/display/intel_quirks.c
> @@ -72,6 +72,12 @@ static void quirk_no_pps_backlight_power_hook(struct
> intel_display *display)
>  	drm_info(display->drm, "Applying no pps backlight power quirk\n");  }
> 
> +static void quirk_edp_max_240hz_hook(struct intel_display *display) {
> +	intel_set_quirk(display, QUIRK_EDP_MAX_240HZ_HOOK);
> +	drm_info(display->drm, "Applying max 240Hz quirk\n"); }
> +
>  static void quirk_fw_sync_len(struct intel_dp *intel_dp)  {
>  	struct intel_display *display = to_intel_display(intel_dp); @@ -120,6
> +126,12 @@ static int intel_dmi_no_pps_backlight(const struct dmi_system_id
> *id)
>  	return 1;
>  }
> 
> +static int intel_dmi_edp_max_240hz(const struct dmi_system_id *id) {
> +	DRM_INFO("Restrict output refreshrate to maximum 240Hz %s\n", id-
> >ident);
> +	return 1;
> +}
> +
>  static const struct intel_dmi_quirk intel_dmi_quirks[] = {
>  	{
>  		.dmi_id_list = &(const struct dmi_system_id[]) { @@ -166,6
> +178,24 @@ static const struct intel_dmi_quirk intel_dmi_quirks[] = {
>  		},
>  		.hook = quirk_no_pps_backlight_power_hook,
>  	},
> +	{
> +		.dmi_id_list = &(const struct dmi_system_id[]) {
> +			{
> +				.callback = intel_dmi_edp_max_240hz,
> +				.ident = "TUXEDO Stellaris 16 Intel Gen7",
> +				.matches =
> {DMI_EXACT_MATCH(DMI_BOARD_NAME, "X6AR5xxY"),
> +				},
> +			},
> +			{
> +				.callback = intel_dmi_edp_max_240hz,
> +				.ident = "TUXEDO Stellaris 16 Intel Gen7",
> +				.matches =
> {DMI_EXACT_MATCH(DMI_BOARD_NAME, "X6AR5xxY_mLED"),
> +				},
> +			},
> +			{ }
> +		},
> +		.hook = quirk_edp_max_240hz_hook,
> +	},
>  };
> 
>  static struct intel_quirk intel_quirks[] = { diff --git
> a/drivers/gpu/drm/i915/display/intel_quirks.h
> b/drivers/gpu/drm/i915/display/intel_quirks.h
> index cafdebda75354..8fe3f3467106a 100644
> --- a/drivers/gpu/drm/i915/display/intel_quirks.h
> +++ b/drivers/gpu/drm/i915/display/intel_quirks.h
> @@ -20,6 +20,7 @@ enum intel_quirk_id {
>  	QUIRK_LVDS_SSC_DISABLE,
>  	QUIRK_NO_PPS_BACKLIGHT_POWER_HOOK,
>  	QUIRK_FW_SYNC_LEN,
> +	QUIRK_EDP_MAX_240HZ_HOOK,
>  };
> 
>  void intel_init_quirks(struct intel_display *display);
> --
> 2.43.0