Re: [PATCH 1/1] drm/i915/display: Add quirk to force backlight type on some TUXEDO devices

[Werner Sembach <wse@tuxedocomputers.com>]

Hi,

any news on this? Should i rebase it to the current linux version?

Best regards,

Werner

Am 22.08.25 um 23:21 schrieb Werner Sembach:
> Hi,
>
> Am 22.07.25 um 13:40 schrieb Werner Sembach:
>> Hi,
>>
>> Am 15.04.25 um 17:48 schrieb Werner Sembach:
>>> Hi,
>>>
>>> Am 11.04.25 um 20:56 schrieb Ville Syrjälä:
>>>> On Fri, Apr 11, 2025 at 05:55:08PM +0200, Werner Sembach wrote:
>>>>> The display backlight on TUXEDO DX1708 and InsanityBook 15 v1 with panels
>>>>> AUO 12701 and AUO 12701 must be forced to INTEL_DP_AUX_BACKLIGHT_ON 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.
>>>> Why aren't you fixing the VBT to be correct in the first place?
>>>
>>> I don't have access to the firmware source code and these are quite old 
>>> devices so I also can't request a fix from the ODM. Besides: it can be quite 
>>> hard to explain to the ODM what exactly the problem is if it doesn't also 
>>> affect Windows.
>>
>> TBH I don't know what VBT stands for, I just assumed it has to to with the 
>> displays firmware?
>>
>> Unlike I wrote in the cover letter we actually still had an affected device 
>> in our archives -> the issue persists and the quirk is still necessary.
> Hope a gentle bump here is ok
>>
>> Best Regards,
>>
>> Werner
>>
>>>
>>> Best regards,
>>>
>>> Werner Sembach
>>>
>>>>
>>>>> Signed-off-by: Werner Sembach <wse@tuxedocomputers.com>
>>>>> Cc: stable@vger.kernel.org
>>>>> ---
>>>>>   .../drm/i915/display/intel_dp_aux_backlight.c | 14 ++++++-
>>>>>   drivers/gpu/drm/i915/display/intel_quirks.c   | 42 +++++++++++++++++++
>>>>>   drivers/gpu/drm/i915/display/intel_quirks.h   |  1 +
>>>>>   3 files changed, 56 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c 
>>>>> b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
>>>>> index c846ef4acf5b2..0cac04c98a3e3 100644
>>>>> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
>>>>> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
>>>>> @@ -34,12 +34,14 @@
>>>>>    * for some reason.
>>>>>    */
>>>>>   +#include <drm/drm_edid.h>
>>>>>   #include "i915_utils.h"
>>>>>   #include "intel_backlight.h"
>>>>>   #include "intel_display_core.h"
>>>>>   #include "intel_display_types.h"
>>>>>   #include "intel_dp.h"
>>>>>   #include "intel_dp_aux_backlight.h"
>>>>> +#include "intel_quirks.h"
>>>>>     /*
>>>>>    * DP AUX registers for Intel's proprietary HDR backlight interface. We 
>>>>> define
>>>>> @@ -607,11 +609,21 @@ int intel_dp_aux_init_backlight_funcs(struct 
>>>>> intel_connector *connector)
>>>>>       struct drm_device *dev = connector->base.dev;
>>>>>       struct intel_panel *panel = &connector->panel;
>>>>>       bool try_intel_interface = false, try_vesa_interface = false;
>>>>> +    int enable_dpcd_backlight;
>>>>> +    u32 pnl_id;
>>>>>         /* Check the VBT and user's module parameters to figure out which
>>>>>        * interfaces to probe
>>>>>        */
>>>>> -    switch (display->params.enable_dpcd_backlight) {
>>>>> +    enable_dpcd_backlight = display->params.enable_dpcd_backlight;
>>>>> +    if (enable_dpcd_backlight == INTEL_DP_AUX_BACKLIGHT_AUTO &&
>>>>> +        intel_has_quirk(display, 
>>>>> QUIRK_AUO_12701_21229_ENABLE_DPCD_BACKLIGHT)) {
>>>>> +        pnl_id = drm_edid_get_panel_id(panel->fixed_edid);
>>>>> +        if (pnl_id == drm_edid_encode_panel_id('A', 'U', 'O', 0x319d) ||
>>>>> +            pnl_id == drm_edid_encode_panel_id('A', 'U', 'O', 0x52ed))
>>>>> +            enable_dpcd_backlight = INTEL_DP_AUX_BACKLIGHT_ON;
>>>>> +    }
>>>>> +    switch (enable_dpcd_backlight) {
>>>>>       case INTEL_DP_AUX_BACKLIGHT_OFF:
>>>>>           return -ENODEV;
>>>>>       case INTEL_DP_AUX_BACKLIGHT_AUTO:
>>>>> diff --git a/drivers/gpu/drm/i915/display/intel_quirks.c 
>>>>> b/drivers/gpu/drm/i915/display/intel_quirks.c
>>>>> index 8b30e9fd936e7..6f724e5712664 100644
>>>>> --- a/drivers/gpu/drm/i915/display/intel_quirks.c
>>>>> +++ b/drivers/gpu/drm/i915/display/intel_quirks.c
>>>>> @@ -78,6 +78,12 @@ static void quirk_fw_sync_len(struct intel_dp *intel_dp)
>>>>>       drm_info(display->drm, "Applying Fast Wake sync pulse count quirk\n");
>>>>>   }
>>>>>   +static void quirk_auo_12701_21229_enable_dpcd_backlight(struct 
>>>>> intel_display *display)
>>>>> +{
>>>>> +    intel_set_quirk(display, QUIRK_AUO_12701_21229_ENABLE_DPCD_BACKLIGHT);
>>>>> +    drm_info(display->drm, "Applying Display AUO Model 12701 and 21229 
>>>>> Enable DPCD Backlight quirk\n");
>>>>> +}
>>>>> +
>>>>>   struct intel_quirk {
>>>>>       int device;
>>>>>       int subsystem_vendor;
>>>>> @@ -118,6 +124,12 @@ static int intel_dmi_no_pps_backlight(const struct 
>>>>> dmi_system_id *id)
>>>>>       return 1;
>>>>>   }
>>>>>   +static int intel_dmi_auo_12701_21229_enable_dpcd_backlight(const struct 
>>>>> dmi_system_id *id)
>>>>> +{
>>>>> +    DRM_INFO("Display AUO model 12701 and 21229 DPCD backlight control on 
>>>>> %s\n", id->ident);
>>>>> +    return 1;
>>>>> +}
>>>>> +
>>>>>   static const struct intel_dmi_quirk intel_dmi_quirks[] = {
>>>>>       {
>>>>>           .dmi_id_list = &(const struct dmi_system_id[]) {
>>>>> @@ -164,6 +176,36 @@ 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_auo_12701_21229_enable_dpcd_backlight,
>>>>> +                .ident = "TUXEDO DX1708",
>>>>> +                .matches = {DMI_MATCH(DMI_BOARD_NAME, "N8xEJEK"),
>>>>> +                },
>>>>> +            },
>>>>> +            {
>>>>> +                .callback = intel_dmi_auo_12701_21229_enable_dpcd_backlight,
>>>>> +                .ident = "TUXEDO InsanityBook 15 v1",
>>>>> +                .matches = {DMI_MATCH(DMI_BOARD_NAME, "P95_HP"),
>>>>> +                },
>>>>> +            },
>>>>> +            {
>>>>> +                .callback = intel_dmi_auo_12701_21229_enable_dpcd_backlight,
>>>>> +                .ident = "TUXEDO InsanityBook 15 v1",
>>>>> +                .matches = {DMI_MATCH(DMI_BOARD_NAME, "P95_HR"),
>>>>> +                },
>>>>> +            },
>>>>> +            {
>>>>> +                .callback = intel_dmi_auo_12701_21229_enable_dpcd_backlight,
>>>>> +                .ident = "TUXEDO InsanityBook 15 v1",
>>>>> +                .matches = {DMI_MATCH(DMI_BOARD_NAME, "P95_HP,HR,HQ"),
>>>>> +                },
>>>>> +            },
>>>>> +            { }
>>>>> +        },
>>>>> +        .hook = quirk_auo_12701_21229_enable_dpcd_backlight,
>>>>> +    },
>>>>>   };
>>>>>     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..38bdbd65d7efb 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_AUO_12701_21229_ENABLE_DPCD_BACKLIGHT,
>>>>>   };
>>>>>     void intel_init_quirks(struct intel_display *display);
>>>>> -- 
>>>>> 2.43.0