Re: [PATCH] media: staging/ipu7: snoop ISYS writes to capture buffers

[Sergey Lebedev]

Hi Manik, Divyamani,

Sakari added you to this patch in October. Is is_snoop = 1 on the
capture pin right for IPU7, and for IPU 7.5, which I could not test?

Christian Murphy sent a different fix for the same rows in August,
which I missed: a clflush of each capture buffer in buf_prepare and
buf_finish, with is_snoop left at 0. If the snoop bit cannot be relied
on, his is the one to take:
https://lore.kernel.org/all/20260824224139.21256-1-christian@xxxxxxxxxxxxx/

With is_snoop = 1, frames holding rows of the buffer's previous fill
went from 301 of 698 and 684 of 697 to none, reading every frame with
the CPU, and 4224x3136 raw at about 790 MB/s still ran at 29.95 fps.
The patch applies to v7.4-rc1 unchanged.

It carries an Assisted-by tag, which 7.4-rc1 no longer accepts; Sakari,
please drop it when applying, or I will resend without it.

Sergey