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

[Maíra Canal]

Hi Ulf,

Given Florian's ack, could you consider picking up this patch for the pm
tree? Thanks!

Best regards,
- Maíra

On 22/06/26 12:29, Florian Fainelli wrote:
> 
> 
> 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 at igalia.com>
> 
> Acked-by: Florian Fainelli <florian.fainelli at 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.