linux-kernel - Re: [PATCH v3 07/15] media: qcom: camss: Capture VFE CSID dependency in a helper function

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: <ddc36a54-1ac9-b7e9-bad4-04a93ee493fd@linaro.org>
Date:   Mon, 28 Aug 2023 20:41:30 +0100
From:   Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To:     Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     rfoss@...nel.org, todor.too@...il.com, agross@...nel.org,
        andersson@...nel.org, konrad.dybcio@...aro.org, mchehab@...nel.org,
        hverkuil-cisco@...all.nl, sakari.ailus@...ux.intel.com,
        andrey.konovalov@...aro.org, linux-media@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 07/15] media: qcom: camss: Capture VFE CSID dependency
 in a helper function

On 28/08/2023 20:40, Laurent Pinchart wrote:
> On Mon, Aug 28, 2023 at 08:37:44PM +0100, Bryan O'Donoghue wrote:
>> On 28/08/2023 19:47, Laurent Pinchart wrote:
>>> Hi Bryan,
>>>
>>> Thank you for the patch.
>>>
>>> On Wed, Aug 23, 2023 at 11:44:36AM +0100, Bryan O'Donoghue wrote:
>>>>   From sdm845 onwards we need to ensure the VFE is powered on prior to
>>>> switching on the CSID.
>>>
>>> Based on the discussions with Konrad in the mail thread, I would record
>>> here the reason for this requirement.
>>>
>>> What happens if you unconditionally power up the VFE prior to switching
>>> the CSID on ? Will this break something on platforms older than SDM845 ?
>>
>> vfe->power_count will bump and you will be fine.
> 
> Then maybe that would be a simpler solution than having a
> device-specific power sequence ?
> 

A fair point.

Worth a try.

---
bod