Re: [PATCH 2/2] remoteproc: qcom: q6v5: Ignore stale handover IRQ delivered on attach

[Abel Vesa]

On 26-07-31 10:56:54, Shawn Guo wrote:
> Commit bb7c5d6f5b41 ("remoteproc: qcom: q6v5: Make handover IRQ one-shot")
> dropped the check that ignored a handover interrupt after handover
> had already been issued, relying instead on disabling the IRQ after
> its first delivery to make it one-shot.
> 
> That is not sufficient for qcom_pas_attach(): when attaching to a
> remote processor that was already booted by the bootloader, handover
> has already happened out-of-band, before this driver ever probed.
> qcom_pas_attach() sets handover_issued = true and unmasks the
> handover IRQ to keep the enable/disable tracking consistent, but the
> transition that signals handover is latched at the interrupt
> controller while masked, so unmasking still delivers that one IRQ.
> 
> Since this driver instance never ran qcom_pas_start() for that boot,
> it never took the proxy power-domain/clock/regulator votes that
> q6v5->handover() releases. Running the handover callback for this
> stale, already-accounted-for signal disables those votes without a
> matching enable, producing:
> 
>   genpd genpd:0:4c00000.remoteproc: Runtime PM usage count underflow!
>   genpd genpd:1:4c00000.remoteproc: Runtime PM usage count underflow!
> 
> Restore the early-return when handover_issued is already set, so a
> stale IRQ delivered on attach is dropped after being disabled instead
> of re-running the handover callback.
> 
> Fixes: bb7c5d6f5b41 ("remoteproc: qcom: q6v5: Make handover IRQ one-shot")
> Assisted-by: Claude:claude-sonnet-5
> Signed-off-by: Shawn Guo <shengchao.guo@xxxxxxxxxxxxxxxx>

Reviewed-by: Abel Vesa <abel.vesa@xxxxxxxxxxxxxxxx>