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<div class="moz-cite-prefix">Thanks for the feedback!<br>
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<div class="moz-cite-prefix">On 06.07.25 13:29, Dmitry Baryshkov
wrote:<br>
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<blockquote type="cite"
cite="mid:27oxphsevfwolf5mpm2vygrmp6wryujwmw65lsb7eqktykdw3z@lahceblqorgn">
<pre wrap="" class="moz-quote-pre">On Thu, Jul 03, 2025 at 11:03:35AM +0200, Robert Mader wrote:
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<pre wrap="" class="moz-quote-pre">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:
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It feels like the current possible_clones is incorrect according to the
documentation. Should there be a Fixes tag?</pre>
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<p>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.</p>
<p>Unfortunately the patch is not easily backportable either way
because of the changes in
<a class="moz-txt-link-freetext" href="https://patchwork.freedesktop.org/series/144091/#rev4">https://patchwork.freedesktop.org/series/144091/#rev4</a> that
recently landed - i.e. 6.15 would need a completely rewritten fix,
and previous kernels don't really need it.</p>
<p>Thus I'd rather leave it out if that's ok with you?<br>
</p>
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cite="mid:27oxphsevfwolf5mpm2vygrmp6wryujwmw65lsb7eqktykdw3z@lahceblqorgn">
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Signed-off-by: Robert Mader <a class="moz-txt-link-rfc2396E" href="mailto:robert.mader@collabora.com"><robert.mader@collabora.com></a>
---
drivers/gpu/drm/vkms/vkms_output.c | 12 ++++++++++++
drivers/gpu/drm/vkms/vkms_writeback.c | 2 ++
2 files changed, 14 insertions(+)
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<pre class="moz-signature" cols="72">--
Robert Mader
Consultant Software Developer
Collabora Ltd.
Platinum Building, St John's Innovation Park, Cambridge CB4 0DS, UK
Registered in England & Wales, no. 5513718</pre>
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