Re: [PATCH v5 3/7] cxl/region: Skip decoder reset on detach for autodiscovered regions

["Koralahalli Channabasappa, Smita" <skoralah@amd.com>]

Hi Jonathan,

On 1/22/2026 8:18 AM, Jonathan Cameron wrote:
> On Thu, 22 Jan 2026 04:55:39 +0000
> Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com> wrote:
> 
>> __cxl_decoder_detach() currently resets decoder programming whenever a
>> region is detached if cxl_config_state is beyond CXL_CONFIG_ACTIVE. For
>> autodiscovered regions, this can incorrectly tear down decoder state
>> that may be relied upon by other consumers or by subsequent ownership
>> decisions.
>>
>> Skip cxl_region_decode_reset() during detach when CXL_REGION_F_AUTO is
>> set.
>>
>> Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> purely on basis we should probably not undo things we didn't do in the
> first place.
> 
> J

Thank you!

I’m re reading Dan’s note here:
https://lore.kernel.org/all/6930dacd6510f_198110020@dwillia2-mobl4.notmuch/

Specifically this part:
"If the administrator actually wants to destroy and reclaim that
physical address space then they need to forcefully de-commit that
auto-assembled region via the @commit sysfs attribute. So that means
commit_store() needs to clear CXL_REGION_F_AUTO to get the decoder reset
to happen."

Today the sysfs commit=0 path inside commit_store() resets decoders 
without the AUTO check whereas the detach path now skips the reset when 
CXL_REGION_F_AUTO is set.

I think the same rationale should apply to the sysfs de-commit path as 
well? I’m trying to understand the implications of not guarding the 
reset with AUTO in commit_store().

Thanks
Smita