From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Sergey Shtylyov <s.shtylyov@omp.ru>
Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org,
Hans de Goede <hdegoede@redhat.com>, Jens Axboe <axboe@kernel.dk>,
Damien Le Moal <damien.lemoal@opensource.wdc.com>
Subject: Re: [PATCH v1 1/2] ata: libahci_platform: Get rid of dup message when IRQ can't be retrieved
Date: Fri, 10 Dec 2021 13:28:35 +0200 [thread overview]
Message-ID: <YbM541VXHoOUsM5+@smile.fi.intel.com> (raw)
In-Reply-To: <7ffe328f-2ba1-4799-5c6a-d48d88c0459d@omp.ru>
On Fri, Dec 10, 2021 at 02:14:15PM +0300, Sergey Shtylyov wrote:
> On 12/10/21 1:44 PM, Andy Shevchenko wrote:
>
> >>>>>>> While at it, drop redundant check for 0 as platform_get_irq() spills
> >>>>>>> out a big WARN() in such case.
> >>>>>>
> >>>>>> And? IRQ0 is still returned! :-(
> >>>>>
> >>>>> It should not be returned in the first place.
> >>>>
> >>>> But it still is, despite the WARN(), right?
> >>>
> >>> So, you admit that there is a code which does that?
> >>
> >> I admit *what*?! That platfrom_get_irq() and its ilk return IRQ0 while they
> >> shouldn't? =)
> >
> > That there is a code beneath platform_get_irq() that returns 0, yes.
>
> Look at the ACPI-specific GpioInt handling code (just above the out_not_found label) --
> I'm not sure the check there is correct -- I'm not very familiar with ACPI, you seem to
> know it much better. :-)
And what is your point here exactly? If == 0 case happens, it will be
immediately WARN() and reported (I hope) since it will mean bug in the code.
> Also, 0 can be specified via the normal IRQ resource. I know of e.g. the Alchemy MIPS SoCs
> that have IRQ0 used by UART0; luckily, currently SoC IRQs are mapped starting at Linux IRQ8
> (but it wasn't the case in the 2.6.1x time frame where we had issue with the serial driver)...
You mixed up HW IRQ with vIRQ. The former one may be 0 and it's completely valid case, while
the second one is not.
> >>> That code should be fixed first. Have you sent a patch?
> >>
> >> Which code?! You got me totally muddled. =)
> >
> > Above mentioned.
>
> What needs to be fixed in this case is the interrupt controller driver.
What do you mean by that? vIRQ is handled by IRQ core, IRQ controller driver
just a mere provider of the resource. And those exceptions for vIRQ == 0
shouldn't be propagated to the platform code or so.
> Quoting Linus
> (imprecisely :-)), IRQ #s should be either mapped starting with #1 or IRQ0 remapped at
> the end of the controller's interrupt range... I currently have no information on the
> platforms requiring such kind of fixing (Alchemy don't seem to need it now)...
Again, do not mix vIRQ (about which Linus ranted) and HW IRQ.
...
> >>>>>>> - if (!irq)
> >>>>>>> - return -EINVAL;
> >>>>>>
> >>>>>> This is prermature -- let's wait till my patch that stops returning IRQ0 from
> >>>>>> platform_get_irq() and friends gets merged....
> >>>>>
> >>>>> What patch?
> >>>>
> >>>> https://marc.info/?l=linux-kernel&m=163623041902285
> >>>>
> >>>>> Does it fix platform_get_irq_optional()?
> >>>>
> >>>> Of course! :-)
> >>>
> >>> Can you share link to lore.kernel.org, please?
> >>> It will make much easier to try and comment.
> >>
> >> I don't know how to uise it yet, and I'm a little busy with other IRQ0 issues ATM,
> A little bit, I meant to type.
No problem. I just haven't got what other IRQ0 issues except fixing
platform_get_irq_optional() et al. could be possibly needed...
> >> so I'm afraid you're on your own here...
> >
> > lore.kernel.org is the official mailing list archive for Linux kernel work
> > AFAIU. Other sites may do whatever they want with that information, so -->
> > they are unreliable. If you wish to follow the better process, use
> > lore.kernel.org. Understanding how it works takes no more than 5 minutes
> > by engineer with your kind of experience with Linux kernel development.
>
> OK, I'll explore this archive when I have time. BTW, does it keep the messages not
> posted to LKML (I tend to only CC LKML if there's no other mailing lists to post to)?
TL;DR: yes.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2021-12-10 11:29 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 14:59 [PATCH v1 1/2] ata: libahci_platform: Get rid of dup message when IRQ can't be retrieved Andy Shevchenko
2021-12-09 14:59 ` [PATCH v1 2/2] ata: libahci_platform: Remove bogus 32-bit DMA mask attempt Andy Shevchenko
2021-12-10 19:34 ` Andy Shevchenko
2021-12-11 0:04 ` Damien Le Moal
2021-12-17 0:58 ` Damien Le Moal
2021-12-17 11:57 ` Andy Shevchenko
2021-12-09 15:21 ` [PATCH v1 1/2] ata: libahci_platform: Get rid of dup message when IRQ can't be retrieved Hans de Goede
2021-12-09 17:24 ` Sergey Shtylyov
2021-12-09 17:42 ` Andy Shevchenko
2021-12-09 18:22 ` Sergey Shtylyov
2021-12-09 19:22 ` Andy Shevchenko
2021-12-09 19:27 ` Andy Shevchenko
2021-12-09 20:31 ` Sergey Shtylyov
2021-12-09 20:29 ` Sergey Shtylyov
2021-12-10 10:44 ` Andy Shevchenko
2021-12-10 11:14 ` Sergey Shtylyov
2021-12-10 11:28 ` Andy Shevchenko [this message]
2021-12-10 17:39 ` Sergey Shtylyov
2021-12-10 17:51 ` Andy Shevchenko
2021-12-09 22:49 ` Damien Le Moal
2021-12-09 22:57 ` Damien Le Moal
2021-12-10 8:47 ` Andy Shevchenko
2021-12-10 16:38 ` Sergey Shtylyov
2021-12-10 17:57 ` Andy Shevchenko
2021-12-10 8:59 ` Sergey Shtylyov
2021-12-10 10:46 ` Andy Shevchenko
2021-12-10 11:19 ` Sergey Shtylyov
2021-12-10 11:36 ` Andy Shevchenko
2021-12-10 17:15 ` Sergei Shtylyov
2021-12-10 17:59 ` Andy Shevchenko
2021-12-10 19:01 ` Sergey Shtylyov
2021-12-10 19:25 ` Andy Shevchenko
2021-12-10 19:30 ` Sergey Shtylyov
2021-12-10 19:35 ` Sergei Shtylyov
2021-12-11 10:13 ` Sergey Shtylyov
2021-12-13 11:26 ` Andy Shevchenko
2021-12-10 23:45 ` Damien Le Moal
2021-12-11 10:25 ` Sergey Shtylyov
2021-12-12 22:39 ` Damien Le Moal
2021-12-13 11:52 ` Andy Shevchenko
2021-12-13 21:36 ` Damien Le Moal
2021-12-13 22:02 ` Andy Shevchenko
2021-12-13 11:49 ` Andy Shevchenko
2021-12-13 11:46 ` Andy Shevchenko
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