Re: [REGRESSION 7.3] drm/amd/display: single-frame scanout corruption on DCN32 at 120 Hz since a637a140ab86

[Mikhail Gavrilov]

Calvin Owens bisected the same artefact to a637a140ab86 on his RX 7900,
with the same parent good, and posted a revert.  On his machine the
band appears within 30 minutes, and the revert removes it:

  https://lore.kernel.org/all/25995707c39c0c191e3ac46c4813f55a7f928403.1793131583.git.calvin@xxxxxxxxxx/

#regzbot monitor: https://lore.kernel.org/all/25995707c39c0c191e3ac46c4813f55a7f928403.1793131583.git.calvin@xxxxxxxxxx/

A correction to my earlier mails, which listed the instruction
constants and the stack among the DMUB windows that a637a140ab86 moves
to GTT.  When the firmware is loaded through the PSP, the default on
these cards, the driver neither copies the instruction constants into
its window nor programs the instruction and stack windows
(dm_dmub_hw_init(), dmub_srv_hw_init()), so the firmware does not run
from the driver's copies of those two.  The windows the driver does set
up -- BSS data, VBIOS, mailbox, trace buffer, firmware state, shared
state and the rest -- did move.

-- 
Thanks,
Mikhail