On 12/09/2016 02:25 PM, Rob Herring wrote:

On Mon, Dec 5, 2016 at 1:01 PM, Guilherme G. Piccoli
[off-list ref] wrote:

quoted

On 12/05/2016 12:28 PM, Rob Herring wrote:

quoted

On Mon, Dec 5, 2016 at 7:59 AM, Guilherme G. Piccoli
[off-list ref] wrote:

quoted

On PowerPC machines some PCI slots might not have level triggered
interrupts capability (also know as level signaled interrupts),
leading of_irq_parse_pci() to complain by presenting error messages
on the kernel log - in this case, the properties "interrupt-map" and
"interrupt-map-mask" are not present on device's node in the device
tree.

This patch introduces a different message for this specific case,
and also reduces its level from error to warning. Besides, we warn
(once) that possibly some PCI slots on the system have no level
triggered interrupts available.
We changed some error return codes too on function of_irq_parse_raw()
in order other failure's cases can be presented in a more precise way.

Before this patch, when an adapter was plugged in a slot without level
interrupts capabilitiy on PowerPC, we saw a generic error message
like this:

    [54.239] pci 002d:70:00.0: of_irq_parse_pci() failed with rc=-22

Now, with this applied, we see the following specific message:

    [16.154] pci 0014:60:00.1: of_irq_parse_pci: no interrupt-map found,
    INTx interrupts not available

Finally, we standardize the error path in of_irq_parse_raw() by always
taking the fail path instead of returning directly from the loop.

Signed-off-by: Guilherme G. Piccoli <redacted>
---

v2:
  * Changed function return code to always return negative values;

Are you sure this is safe? This is tricky because of differing values
of NO_IRQ (0 or -1).

Thanks Rob, but this is purely bad wording from myself. I'm sorry - I
meant to say that I changed only my positive return code (that was
suggested to be removed in the prior revision) to negative return code!

So, I changed only code I added myself in v1 =)

quoted

quoted

  * Improved/simplified warning outputs;
  * Changed some return codes and some error paths in of_irq_parse_raw()
in order to be more precise/consistent;

This too could have some side effects on callers.

Not saying don't do these changes, just need some assurances this has
been considered.

Thanks for your attention. I performed a quick investigation before
changing this, all the places that use the return values are just
getting "true/false" information from that, meaning they just are
comparing to 0 basically. So change -EINVAL to -ENOENT wouldn't hurt any
user of these return values, it'll only become more informative IMHO.

Now, regarding the only error path that was changed: for some reason,
this was the only place in which we didn't goto fail label in case of
failure - it was added by a legacy commit from Ben, dated from 2006:
006b64de60 ("[POWERPC] Make OF irq map code detect more error cases").
Then it was carried by Grant Likely's commit 7dc2e1134a ("of/irq: merge
irq mapping code"), 6-year old commit.
I wasn't able to imagine a scenario in which changing this would break
something; I believe the change improve consistency, but I'd remove it
if you or somebody else thinks it worth be removed.

Okay. It's a bit late for 4.10 now and want this to be in -next for a
while, so I'll queue it after the merge window.

OK, perfect! Thanks Rob
Cheers,


Guilherme

Rob