Re: [PATCH] pmdomain: bcm: bcm2835-power: Raise ASB poll timeout to 100us

[Florian Fainelli <florian.fainelli@broadcom.com>]

On 5/30/2026 9:46 PM, Maíra Canal wrote:
> Commit 18605b1b936b ("pmdomain: bcm: bcm2835-power: Increase ASB control
> timeout") raised the ASB handshake polling budget from 1us to 5us.
> Surveying the pmdomain subsystem, 5us is still one of the smallest polling
> budgets by a wide margin. Comparable handshakes in other drivers use:
> 
>    - 100us : starfive jh71xx-pmu, apple pmgr-pwrstate
>    - 1ms   : renesas rcar-sysc, rmobile-sysc (power-on)
>    - 10ms  : renesas rcar-gen4-sysc, sunxi sun55i-pck600
>    - 1s    : mediatek mtk-pm-domains, mtk-scpsys
> 
> Raise the BCM2835 timeout to 100us, matching analogous drivers. 100us is
> still negligible relative to a power-domain transition and gives the V3D
> master ASB substantially more headroom to drain under heavy workloads,
> assuring us that the timeout is enough for any scenario.
> 
> Signed-off-by: Maíra Canal <mcanal@igalia.com>

Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>

The response I got from our design team is that turning of the the 
"slave" should be immediate as it does not support multiple outstanding 
transactions, it's the "master" that might requiring bleeding out 
in-flight transactions and for which a longer timeout seems reasonable.
-- 
Florian