Thanks for the feedback!
On 06.07.25 13:29, Dmitry Baryshkov wrote:
On Thu, Jul 03, 2025 at 11:03:35AM +0200, Robert Mader wrote:
Since commit 41b4b11da0215 ("drm: Add valid clones check") setting
the `possible_clones` values is a hard requirement for cloning.
`vkms` supports cloning for writeback connectors in order to capture
CRTC content, however that broke with said commit.
Writeback connectors are created on a per-CRTC basis, thus mark
every non-writeback connector that is compatible with a given CRTC
as possible clone - and vice-versa.
Using a default configuration, the corresponding `drm_info` output
changes from:
It feels like the current possible_clones is incorrect according to the
documentation. Should there be a Fixes tag?
The issue is that possible_clones was never explicitly set, making it
fall back to the default value - every encoder only being compatible
with itself. So candidates for a Fixes tag would be either the initial
implementation of the writeback connector in vkms - or the commit that
started enforcing correct values ("drm: Add valid clones check") as
previously the values where simply ignored.
Unfortunately the patch is not easily backportable either way because of
the changes in https://patchwork.freedesktop.org/series/144091/#rev4
that recently landed - i.e. 6.15 would need a completely rewritten fix,
and previous kernels don't really need it.
Thus I'd rather leave it out if that's ok with you?
Signed-off-by: Robert Mader<robert.ma...@collabora.com>
---
drivers/gpu/drm/vkms/vkms_output.c | 12 ++++++++++++
drivers/gpu/drm/vkms/vkms_writeback.c | 2 ++
2 files changed, 14 insertions(+)
--
Robert Mader
Consultant Software Developer
Collabora Ltd.
Platinum Building, St John's Innovation Park, Cambridge CB4 0DS, UK
Registered in England & Wales, no. 5513718
