Re: [PATCH v4 0/4] HDMI 2.1 VRR and ALLM support

[Adolfo <adolfotregosa@gmail.com>]

I patched kernel 7.3-rc1 with the passive-VRR patches, but VRR is not 
engaging while on the desktop, only in game.

On 01/09/2026 20:15, Zuo, Jerry wrote:
> AMD General
>
>> -----Original Message-----
>> From: Adolfo <adolfotregosa@gmail.com>
>> Sent: Monday, August 31, 2026 14:49
>> To: Zuo, Jerry <Jerry.Zuo@amd.com>; amd-gfx@lists.freedesktop.org
>> Cc: dri-devel@lists.freedesktop.org; Wentland, Harry
>> <Harry.Wentland@amd.com>; Tomasz Pakuła
>> <tomasz.pakula.oficjalny@gmail.com>; daniel@fooishbar.org
>> Subject: Re: [PATCH v4 0/4] HDMI 2.1 VRR and ALLM support
>>
>> [You don't often get email from adolfotregosa@gmail.com. Learn why this is
>> important at https://aka.ms/LearnAboutSenderIdentification ]
>>
>> I patched kernel 7.3-rc1, and I have KDE's Adaptive Sync property set to
>> Automatic (Always makes the display gamma flicker). VRR itself is only
>> engaged when entering a game.
>>
>> My display (an LG C1 connected through an Onkyo RZ70 AVR) shows "fixed"
>> when VRR is not active. While this seems logical, it causes the display to go
>> blank every time I enter or exit a game, or, even worse, when I alt-tab while in
>> a game.
>>
>> In my case, I can have periods of up to 10 seconds with no image while the
>> devices in the HDMI chain disagree with each other, and sometimes I lose the
>> image completely.
>>
>> A kernel parameter to force VRR to always be enabled should be available.
>> This would prevent these signal-switching problems, and it is how "FreeSync"
>> actually works and also with the unofficial kernel patches for AMD HDMI 2.1
>> + VRR on kernel 7.2.
>>
>> There is also some evidence that keeping VRR active can avoid the mode-
>> switch behavior seen on some TVs when VRR is enabled or disabled.
> Thanks for your feedback. Regarding to your concern, I've uploaded another
> series of patches for "passive VRR". Please check and see if that works for you.
>
> Regards,
> Jerry
>
>> On 14/08/2026 17:43, Fangzhi Zuo wrote:
>>> This series adds HDMI 2.1 gaming support to amdgpu: Variable Refresh
>>> Rate
>>> (VRR) derived from the HDMI Forum VSDB (HF-VSDB), and Auto Low-
>> Latency
>>> Mode (ALLM). It builds on a drm/edid patch that parses the HF-VSDB
>>> gaming capabilities into struct drm_hdmi_info.
>>>
>>>     - Patch 1 reports FreeSync from the AMD VSDB (existing mechanism).
>>>     - Patch 2 (drm/edid) parses the HF-VSDB VRR range and ALLM bit.
>>>     - Patch 3 enables VRR from the HF-VSDB when the AMD VSDB has no
>> range.
>>>     - Patch 4 signals ALLM_Mode in the HF-VSIF when Gaming-VRR is active.
>>>
>>> v1:
>>> https://lore.kernel.org/amd-gfx/20260730171754.704049-1-jerry.zuo@amd.
>>> com/
>>> v2:
>>> https://lore.kernel.org/amd-gfx/20260806205449.16806-1-jerry.zuo@amd.c
>>> om/
>>> v3:
>>> https://lore.kernel.org/amd-gfx/20260811003921.1398292-1-
>> jerry.zuo@amd
>>> .com/
>>>
>>> Changes since v3:
>>>     - Drop the content-type based ALLM heuristic. ALLM_Mode is now set
>> only
>>>       for the mandatory Gaming-VRR case (VRR_EN=1 with a sink that
>> advertises
>>>       ALLM), per HDMI 2.1 Section 7.6.6; it is no longer derived from the
>>>       content type.
>>>
>>> Changes since v2:
>>>     - Fix coding-style issues in the VTEM info-packet code.
>>>
>>> Fangzhi Zuo (3):
>>>     drm/amd/display: Add 2.1 FreeSync support for AMD VSDB EDID Block
>>>     drm/amd/display: Add HDMI 2.1 VRR support from HF-VSDB
>>>     drm/amd/display: Enable HDMI ALLM for Gaming-VRR
>>>
>>> Tomasz Pakuła (1):
>>>     drm/edid: parse HDMI 2.1 gaming (ALLM/VRR) capabilities from
>>> HF-VSDB
>>>
>>>    .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |   5 +-
>>>    .../display/amdgpu_dm/amdgpu_dm_connector.c   |  71 +++++++++++-
>>>    .../display/amdgpu_dm/amdgpu_dm_freesync.c    |  41 +++++++
>>>    .../amd/display/modules/inc/mod_info_packet.h |   4 +
>>>    .../display/modules/info_packet/info_packet.c | 109 ++++++++++++++++++
>>>    drivers/gpu/drm/drm_edid.c                    |  42 +++++++
>>>    include/drm/drm_connector.h                   |  47 ++++++++
>>>    7 files changed, 317 insertions(+), 2 deletions(-)
>>>
>>>
>>> base-commit: de2622bbc20276eaaaafa8fdbd374ace1ced28dc