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Message-ID: <d9b65672-07e0-40ba-a882-1db59cb7ad3c@amd.com>
Date: Tue, 24 Jun 2025 14:33:27 +0000
From: "Limonciello, Mario" <Mario.Limonciello@....com>
To: Werner Sembach <wse@...edocomputers.com>, Rodrigo Siqueira
<siqueira@...lia.com>
CC: "Wentland, Harry" <Harry.Wentland@....com>, "Li, Sun peng (Leo)"
<Sunpeng.Li@....com>, "Deucher, Alexander" <Alexander.Deucher@....com>,
"Koenig, Christian" <Christian.Koenig@....com>, "airlied@...il.com"
<airlied@...il.com>, "simona@...ll.ch" <simona@...ll.ch>,
"amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "Hung, Alex"
<Alex.Hung@....com>, "Wheeler, Daniel" <Daniel.Wheeler@....com>
Subject: Re: [PATCH 1/1] drm/amd/display: Add quirk to force backlight type on
some TUXEDO devices
On 6/24/25 4:47 AM, Werner Sembach wrote:
>
> Am 24.06.25 um 07:45 schrieb Mario Limonciello:
>> On 6/24/2025 12:42 AM, Werner Sembach wrote:
>>> Hi Mario,
>>>
>>> Am 23.06.25 um 21:42 schrieb Limonciello, Mario:
>>>> On 6/23/25 2:13 PM, Rodrigo Siqueira wrote:
>>>>> On 06/23, Werner Sembach wrote:
>>>>>> 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;
>>>>>>> + }
>>>>> It lgtm,
>>>>>
>>>>> Additionally, I believe this is safe to merge since it only affects a
>>>>> specific device. Perhaps display folks would like to include this as
>>>>> part of this week's promotion? Anyway, Cc other devs from the display.
>>>>>
>>>>> Reviewed-by: Rodrigo Siqueira <siqueira@...lia.com>
>>>> That's a bit odd that aux based B/L control wouldn't work. Are these
>>>> both OLED panels? What debugging have you done thus far with them?
>>>> What kernel base?
>>>>
>>>> Could you repro on 6.16-rc3?
>>>
>>> Sadly our archive is missing this panel + device combination. This
>>> patch is based on our install script that sets this fix via boot
>>> parameters since the release of these devices.
>>>
>>> So the quirk is field proven, but I can't actively test it anymore.
>>>
>>> Best regards,
>>>
>>> Werner
>>>
>>
>> Do you recall what kernel version you were doing it with? I'm just
>> wondering if AUX brightness control had a bug with such a kernel.
> We shipped the device in 2021 with Ubuntu focal, so the kernel probably
> was 5.8 or 5.11 (in theory it also could have been 5.4 or whatever the
> Ubuntu OEM kernel was at that time).
If it was 5.4 then that didn't yet have OLED backlight control support.
It was first introduced here:
https://github.com/torvalds/linux/commit/945628101be55833a63355510d4b6c934183deab
Then even as recent as 5.12 I see that there was a module parameter for
problems.
https://github.com/torvalds/linux/commit/7a46f05e5e163c00e41892e671294286e53fe15c
But then there were also changes for aux control using the correct DC
API in 5.12 too:
https://github.com/torvalds/linux/commit/0ad3e64eb46d8c47de3af552e282894e3893e973
>>
>> Do you have this panel on some other hardware perhaps?
> Probably not. I will ask however.
>> Or could you send a call out to get some testing done?
>
> An idea I also had in the past to plug this and similar holes in your
> archive, but no "process" for this in place yet.
I'm sorry but I'm not comfortable picking up this technical debt that
will never be removable upstream without proper debugging on what the
"real" problem is.
Recently I have been working on changes to brightness control in
amdgpu_dm and personally validated it working properly on panels that
use aux control for brightness this past kernel cycle or two.
So please help track down one of these panels, either from you guys on
another system, or a call to users with these systems to help.
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