Re: [PATCH] sh: Avoid using IRQ0 on SH3 and SH4

Hi Guenter!

On Thu, 2023-07-06 at 06:57 -0700, Guenter Roeck wrote:
> On Thu, Jun 01, 2023 at 11:22:17PM +0300, Sergey Shtylyov wrote:
> > IRQ0 is no longer returned by platform_get_irq() and its ilk -- they now
> > return -EINVAL instead.  However, the kernel code supporting SH3/4-based
> > SoCs still maps the IRQ #s starting at 0 -- modify that code to start the
> > IRQ #s from 16 instead.
> > 
> > The patch should mostly affect the AP-SH4A-3A/AP-SH4AD-0A boards as they
> > indeed are using IRQ0 for the SMSC911x compatible Ethernet chip.
> > 
> 
> Unfortunately it also affects all sh4 emulations in qemu, and results in
> boot stalls with those. There isn't a relevant log to attach because there
> is no error message - booting just stalls until the emulation is aborted.
> 
> Reverting this patch fixes the problem.
> 
> Bisect log is attached for reference. Note that bisect requires applying
> commit 7497840d462c ("sh: Provide unxlate_dev_mem_ptr() in asm/io.h"),
> which is also the reason why the problem was not observed earlier since
> it was hiding behind a build failure.

Interesting. My naive understanding was that IRQ0 is no longer usable in the
kernel as Sergey claimed. Was that not correct?

Adrian

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