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Am 16.05.22 um 19:49 schrieb Ernst Sjöstrand:<br>
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<div dir="ltr" class="gmail_attr">Den mån 16 maj 2022 kl 17:13
skrev Alex Deucher <<a
href="mailto:alexdeucher@gmail.com" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">alexdeucher@gmail.com</a>>:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">On Sun, May 15, 2022 at
11:46 AM Ernst Sjöstrand <<a
href="mailto:ernstp@gmail.com" target="_blank"
moz-do-not-send="true" class="moz-txt-link-freetext">ernstp@gmail.com</a>>
wrote:<br>
><br>
> smatch found this problem on amd-staging-drm-next:<br>
><br>
> drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c:1443
amdgpu_discovery_get_vcn_info() error: buffer overflow
'adev->vcn.vcn_codec_disable_mask' 2 <= 3<br>
><br>
> This is caused by:<br>
> #define AMDGPU_MAX_VCN_INSTANCES 2<br>
> #define VCN_INFO_TABLE_MAX_NUM_INSTANCES 4<br>
><br>
> Can we just drop VCN_INFO_TABLE_MAX_NUM_INSTANCES
completely and use AMDGPU_MAX_VCN_INSTANCES everywhere
instead (and bump it to 4)?<br>
<br>
We should be able to bump AMDGPU_MAX_VCN_INSTANCES to 4
(although it<br>
would waste some memory in the places it is used at this
point).<br>
VCN_INFO_TABLE_MAX_NUM_INSTANCES is part of a firmware
structure so we<br>
can't change that without breaking the firmware structure.<br>
<br>
Alex<br>
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<div style="font-family:arial,helvetica,sans-serif"
class="gmail_default">It would be nice to get rid of this
pattern and make sure it doesn't happen again when the VCN
info table is raised to 5.</div>
<div style="font-family:arial,helvetica,sans-serif"
class="gmail_default">It's very similar to the
HWIP_MAX_INSTANCE issue.</div>
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<br>
No, as Alex explained that distinction is intentional.<br>
<br>
The firmware definition is 4 for future extensions, that doesn't
mean that this is currently used.<br>
<br>
There is currently simply no need to set AMDGPU_MAX_VCN_INSTANCES to
more than 2.<br>
<br>
Regards,<br>
Christian.<br>
<br>
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<div style="font-family:arial,helvetica,sans-serif"
class="gmail_default">//E<br>
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