linux-kernel - Re: [PATCH v2] mux: mmio: Add suspend and resume support

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: <30397c99-936e-4abb-b214-fca6ce95c2bb@bootlin.com>
Date: Wed, 4 Dec 2024 15:14:31 +0100
From: Thomas Richard <thomas.richard@...tlin.com>
To: Andrew Davis <afd@...com>, Peter Rosin <peda@...ntia.se>
Cc: linux-kernel@...r.kernel.org, gregory.clement@...tlin.com,
 theo.lebrun@...tlin.com, thomas.petazzoni@...tlin.com, u-kumar1@...com
Subject: Re: [PATCH v2] mux: mmio: Add suspend and resume support

On 12/4/24 14:53, Andrew Davis wrote:
> On 9/11/24 3:53 AM, Thomas Richard wrote:
>> The status of each mux is read during suspend and stored in the private
>> memory of the mux_chip.
>> Then the state is restored during the resume.
>>
>> Signed-off-by: Thomas Richard <thomas.richard@...tlin.com>
>> ---
>> In this second version, as discussed with Peter, everything is done in
>> the
>> mmio-mux driver.
>> A mux_mmio_set() function was added, and used during suspend stage to get
>> the status of the of the muxes.
>> This status is stored in the private memory of the mux_chip.
>> ---
>> Changes in v2:
>> - Remove all modifications done in the mux subsystem
>> - Add a mux_mmio_set()
>> - Read the status of muxes during suspend and store in the private memory
>>    of the mux_chip.
> 
> Do you need this private memory? Since this is already using regmap, why
> not use the regmap cache, then you can restore all the values on resume
> with a simple call to regcache_sync().
The regmap can be set without cache.
As you inherit the regmap, you cannot assume that the cache is enabled.

Thomas