linux-kernel - Re: [PATCH] mailbox: pcc: don't zero error register

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Message-ID: <20251127-cherubic-chicken-of-honeydew-075eac@sudeepholla>
Date: Thu, 27 Nov 2025 14:37:45 +0000
From: Sudeep Holla <sudeep.holla@....com>
To: Punit Agrawal <punit.agrawal@....qualcomm.com>
Cc: jassisinghbrar@...il.com, linux-acpi@...r.kernel.org,
	Sudeep Holla <sudeep.holla@....com>, linux-kernel@...r.kernel.org,
	Jamie Iles <jamie.iles@....qualcomm.com>
Subject: Re: [PATCH] mailbox: pcc: don't zero error register

On Wed, Nov 05, 2025 at 02:42:29PM +0000, Punit Agrawal wrote:
> From: Jamie Iles <jamie.iles@....qualcomm.com>
> 
> The error status mask for a type 3/4 subspace is used for reading the
> error status, and the bitwise inverse is used for clearing the error
> with the intent being to preserve any of the non-error bits.  However,
> we were previously applying the mask to extract the status and then
> applying the inverse to the result which ended up clearing all bits.
> 
> Instead, store the inverse mask in the preserve mask and then use that
> on the original value read from the error status so that only the error
> is cleared.
> 
> Fixes: c45ded7e1135 ("mailbox: pcc: Add support for PCCT extended PCC subspaces(type 3/4)")

Good catch!

Reviewed-by: Sudeep Holla <sudeep.holla@....com>

-- 
Regards,
Sudeep