Re: [PATCH v4] PCI: Reduce warnings on possible RW1C corruption

From: Florian Fainelli
Date: Thu Aug 06 2020 - 14:36:04 EST




On 8/5/2020 9:14 PM, Mark Tomlinson wrote:
> For hardware that only supports 32-bit writes to PCI there is the
> possibility of clearing RW1C (write-one-to-clear) bits. A rate-limited
> messages was introduced by fb2659230120, but rate-limiting is not the
> best choice here. Some devices may not show the warnings they should if
> another device has just produced a bunch of warnings. Also, the number
> of messages can be a nuisance on devices which are otherwise working
> fine.
>
> This patch changes the ratelimit to a single warning per bus. This
> ensures no bus is 'starved' of emitting a warning and also that there
> isn't a continuous stream of warnings. It would be preferable to have a
> warning per device, but the pci_dev structure is not available here, and
> a lookup from devfn would be far too slow.
>
> Suggested-by: Bjorn Helgaas <helgaas@xxxxxxxxxx>
> Fixes: fb2659230120 ("PCI: Warn on possible RW1C corruption for sub-32 bit config writes")
> Signed-off-by: Mark Tomlinson <mark.tomlinson@xxxxxxxxxxxxxxxxxxx>

Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
--
Florian