linux-kernel - Re: [PATCH RFT 13/14] drm/msm/a6xx: Drop cfg->ubwc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5f5e512c-ae0e-43aa-856f-06820ac4b147@oss.qualcomm.com>
Date: Fri, 9 May 2025 15:17:44 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Connor Abbott <cwabbott0@...il.com>,
        Konrad Dybcio <konradybcio@...nel.org>
Cc: Bjorn Andersson <andersson@...nel.org>, Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Akhil P Oommen <quic_akhilpo@...cinc.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org
Subject: Re: [PATCH RFT 13/14] drm/msm/a6xx: Drop cfg->ubwc_swizzle override

On 5/8/25 9:26 PM, Connor Abbott wrote:
> On Thu, May 8, 2025 at 2:14 PM Konrad Dybcio <konradybcio@...nel.org> wrote:
>>
>> From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
>>
>> On A663 (SA8775P) the value matches exactly.
>>
>> On A610, the value matches on SM6115, but is different on SM6125. That
>> turns out not to be a problem, as the bits that differ aren't even
>> interpreted.
> 
> This is definitely going to break userspace, because the kernel
> doesn't expose the UBWC version, instead exposing just the swizzle and
> userspace expects that it sets the right value for older UBWC versions
> before it became configurable (0x7 for UBWC 1.0 and 0x6 for 2.0-3.0).
> It looks like the data for SM6125 is just wrong.

Oh that's sad.. I'll drop this commit

Konrad