linux-kernel - Re: [PATCH 1/1] drm/amd/display: Add quirk to force backlight type on some TUXEDO devices

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <08ceaa42-a12c-4bd4-bb75-b71126a60688@tuxedocomputers.com>
Date: Mon, 23 Jun 2025 19:44:48 +0200
From: Werner Sembach <wse@...edocomputers.com>
To: harry.wentland@....com, sunpeng.li@....com, siqueira@...lia.com,
 alexander.deucher@....com, christian.koenig@....com, airlied@...il.com,
 simona@...ll.ch
Cc: amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] drm/amd/display: Add quirk to force backlight type on
 some TUXEDO devices

gentle bump

Am 09.04.25 um 18:27 schrieb Werner Sembach:
> The display backlight on TUXEDO Polaris AMD Gen2 and Gen3 with panels
> BOE 2420 and BOE 2423 must be forced to pwn controlled to be able to
> control the brightness.
>
> This could already be archived via a module parameter, but this patch adds
> a quirk to apply this by default on the mentioned device + panel
> combinations.
>
> Signed-off-by: Werner Sembach <wse@...edocomputers.com>
> Cc: stable@...r.kernel.org
> ---
>   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 32 ++++++++++++++++++-
>   1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 39df45f652b32..2bad6274ad8ff 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -1625,11 +1625,13 @@ static bool dm_should_disable_stutter(struct pci_dev *pdev)
>   struct amdgpu_dm_quirks {
>   	bool aux_hpd_discon;
>   	bool support_edp0_on_dp1;
> +	bool boe_2420_2423_bl_force_pwm;
>   };
>   
>   static struct amdgpu_dm_quirks quirk_entries = {
>   	.aux_hpd_discon = false,
> -	.support_edp0_on_dp1 = false
> +	.support_edp0_on_dp1 = false,
> +	.boe_2420_2423_bl_force_pwm = false
>   };
>   
>   static int edp0_on_dp1_callback(const struct dmi_system_id *id)
> @@ -1644,6 +1646,12 @@ static int aux_hpd_discon_callback(const struct dmi_system_id *id)
>   	return 0;
>   }
>   
> +static int boe_2420_2423_bl_force_pwm_callback(const struct dmi_system_id *id)
> +{
> +	quirk_entries.boe_2420_2423_bl_force_pwm = true;
> +	return 0;
> +}
> +
>   static const struct dmi_system_id dmi_quirk_table[] = {
>   	{
>   		.callback = aux_hpd_discon_callback,
> @@ -1722,6 +1730,20 @@ static const struct dmi_system_id dmi_quirk_table[] = {
>   			DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 665 16 inch G11 Notebook PC"),
>   		},
>   	},
> +	{
> +		// TUXEDO Polaris AMD Gen2
> +		.callback = boe_2420_2423_bl_force_pwm_callback,
> +		.matches = {
> +			DMI_MATCH(DMI_BOARD_NAME, "GMxNGxx"),
> +		},
> +	},
> +	{
> +		// TUXEDO Polaris AMD Gen3
> +		.callback = boe_2420_2423_bl_force_pwm_callback,
> +		.matches = {
> +			DMI_MATCH(DMI_BOARD_NAME, "GMxZGxx"),
> +		},
> +	},
>   	{}
>   	/* TODO: refactor this from a fixed table to a dynamic option */
>   };
> @@ -3586,6 +3608,7 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
>   	struct amdgpu_device *adev;
>   	struct drm_luminance_range_info *luminance_range;
>   	int min_input_signal_override;
> +	u32 panel;
>   
>   	if (aconnector->bl_idx == -1 ||
>   	    aconnector->dc_link->connector_signal != SIGNAL_TYPE_EDP)
> @@ -3610,6 +3633,13 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
>   		caps->aux_support = false;
>   	else if (amdgpu_backlight == 1)
>   		caps->aux_support = true;
> +	else if (amdgpu_backlight == -1 &&
> +		 quirk_entries.boe_2420_2423_bl_force_pwm) {
> +		panel = drm_edid_get_panel_id(aconnector->drm_edid);
> +		if (panel == drm_edid_encode_panel_id('B', 'O', 'E', 0x0974) ||
> +		    panel == drm_edid_encode_panel_id('B', 'O', 'E', 0x0977))
> +			caps->aux_support = false;
> +	}
>   	if (caps->aux_support)
>   		aconnector->dc_link->backlight_control_type = BACKLIGHT_CONTROL_AMD_AUX;
>