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
