[PATCH 0/2] phy: hdmi: Add FRL TxFFE level control

[Cristian Ciocaltea]

On 3/30/26 11:57 AM, Vladimir Oltean wrote:
> On Sat, Mar 28, 2026 at 03:54:53PM +0200, Cristian Ciocaltea wrote:
>> During HDMI 2.1 Fixed Rate Link training, the source and sink may
>> negotiate a Transmitter Feed Forward Equalizer (TxFFE) level to
>> compensate for signal quality degradation on the physical channel.  The
>> source starts at level 0 and may increment it up to a maximum agreed
>> upon during LTS3 in response to persistent link failures reported by the
>> sink.  TxFFE adjustment is optional and entirely independent of the FRL
>> rate and lane count selection.
>>
>> Patch 1 extends the HDMI PHY configuration API with two new fields in
>> the frl sub-struct: ffe_level to carry the requested level, and a
>> set_ffe_level flag that switches the semantics of a phy_configure() call
>> to a pure equalizer update, leaving all other fields ignored.
>>
>> Patch 2 implements the new interface in the Rockchip Samsung HDPTX PHY
>> driver.
>>
>> The series depends on the "[PATCH 0/6] phy: rockchip: samsung-hdptx:
>> Clock fixes and API transition cleanups" patchset:
>>
>> https://lore.kernel.org/all/20260227-hdptx-clk-fixes-v1-0-f998f2762d0f@collabora.com/
>>
>> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea at collabora.com>
>> ---
>> Cristian Ciocaltea (2):
>>       phy: hdmi: Add optional FRL TxFFE config options
>>       phy: rockchip: samsung-hdptx: Add support for FRL TxFFE level control
>>
>>  drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c | 74 +++++++++++++++++++++--
>>  include/linux/phy/phy-hdmi.h                      |  6 ++
>>  2 files changed, 75 insertions(+), 5 deletions(-)
>> ---
>> base-commit: f7b64ed948718290209074a50bb0df17e5944873
>> change-id: 20260328-hdptx-ffe-a89c51e66904
>> prerequisite-change-id: 20260227-hdptx-clk-fixes-47426632f862:v1
>> prerequisite-patch-id: 5c1d442fae39103bb758f54738aff33d2491401d
>> prerequisite-patch-id: b86f30292308345387d2a6b50949ad040b931592
>> prerequisite-patch-id: b1335105db9177cb10c64ed1bf0867832e6aac2f
>> prerequisite-patch-id: 83db6603d13e19f239e89fde2b26366eb0106b7e
>> prerequisite-patch-id: b534395ad315811861f11859a3946f65c90c631a
>> prerequisite-patch-id: f9637e57c902f35218cda658397416f84f7285cb
> 
> Sorry for my ignorance; who is supposed to act upon this git-format-patch
> base tree information and in what way?
> 
> As things stand today, the build infrastructure we have in place will
> not be able to apply and test your series unless it applies directly
> onto the linux-phy/next branch.

Oh, I assumed that since b4 makes managing series dependencies straightforward
on the preparation/submission side, there would be similar tooling support on
the build/integration side as well.