Re: [patch V2 43/46] genirq/msi: Provide and use msi_domain_set_default_info_flags()

[Thomas Gleixner]

On Thu, Aug 27 2020 at 09:17, Marc Zyngier wrote:
> On 2020-08-26 12:17, Thomas Gleixner wrote:
>>  #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
>> +void msi_domain_set_default_info_flags(struct msi_domain_info *info)
>> +{
>> +	/* Required so that a device latches a valid MSI message on startup 
>> */
>> +	info->flags |= MSI_FLAG_ACTIVATE_EARLY;
>
> As far as I remember the story behind this flag (it's been a while),
> it was working around a PCI-specific issue, hence being located in
> the PCI code.

Yes. Some cards misbehave when there is no valid message programmed and
MSI is enabled.

> Now, the "program the MSI before enabling it" concept makes sense no
> matter what bus this is on, and I wonder why we are even keeping this
> flag around.

> Can't we just drop it together with the check in
> msi_domain_alloc_irqs()?

I'm fine with that.

Thanks,

        tglx