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Date:   Thu, 28 Apr 2022 08:13:41 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Sergey Shtylyov <s.shtylyov@omp.ru>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        linux-kernel@vger.kernel.org, Marc Zyngier <maz@kernel.org>
Subject: Re: [PATCH v2] platform: finally disallow IRQ0 in platform_get_irq()
 and its ilk
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On Wed, Apr 27, 2022 at 09:59:41PM +0300, Sergey Shtylyov wrote:
> Hello!
> 
> On 4/26/22 1:46 PM, Greg Kroah-Hartman wrote:
> 
> >> The commit a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is
> >> invalid") only calls WARN() when IRQ0 is about to be returned, however
> >> using IRQ0 is considered invalid (according to Linus) outside the arch/
> >> code where it's used by the i8253 drivers. Many driver subsystems treat
> >> 0 specially (e.g. as an indication of the polling mode by libata), so
> >> the users of platform_get_irq[_byname]() in them would have to filter
> >> out IRQ0 explicitly and this (quite obviously) doesn't scale...
> >> Let's finally get this straight and return -EINVAL instead of IRQ0!
> >>
> >> Fixes: a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is invalid")
> >> Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
> >> Acked-by: Marc Zyngier <maz@kernel.org>
> 
> [...]
> 
> > Ok, let's try this now.
> 
>    Well, better late than never! :-)
> 
> > Worst case, we revert it later :)
> 
>    Please just don't revert it outright on the 1st issue report -- give me time
> to look at the issue(s) reported...
>    BTW, I've CC'ed you on the SH patch that avoids using IRQ0. Please help to
> merge it (v1/v2 were posted on February 11th and there was no motion since then)!

I can't merge that until a sh maintainer acks it.  Is that arch even
still alive?

thanks,

greg k-h