Re: [PATCH] acpi: apei: clear error status before acknowledging the error

[Baicar, Tyler]

On 7/31/2017 11:44 AM, Baicar, Tyler wrote:
> On 7/31/2017 11:00 AM, Luck, Tony wrote:
> > On Mon, Jul 31, 2017 at 10:15:27AM -0600, Baicar, Tyler wrote:
> > > I think the better thing to do in this case is still send the ack. If
> > > ghes_read_estatus() fails, then
> > > either we are unable to read the estatus or the estatus is 
> > > empty/invalid.
> > Right now we silently handle that failure of ghes_read_estatus(). That
> > might be hiding some Linux bugs if we are calling ghes_proc() in cases
> > where we shouldn't.
> >
> > Perhaps we should have something like this, so if systems do start 
> > acting
> > weirdly there will be a note that we took this path:
> >
> >     rc = ghes_read_estatus(ghes, 0);
> >     if (rc) {
> >         pr_notice("surprise failure reading ghes estatus\n");
> >         goto out;
> >     }
> Thank you Tony for the feedback, I can add a print like this in the 
> next version. I'll verify that
> rc is not -ENOENT though so we don't print it on empty scenarios since 
> the polled source
> will be hitting this path frequently.
Hi Tony,

I think I'm going to avoid adding this print, the failures are reported 
in prints in ghes_read_estatus(), so it looks a little redundant:

[  133.601165] [Firmware Warn]: GHES: Failed to read error status block!
[  133.601167] surprise failure reading GHES estatus

Thanks,
Tyler
> > > If we do not send the ack, then we will be in a scenario where FW 
> > > will not
> > > send any more errors.
> > We might ACK something that the firmware didn't send, which may
> > lead to other problems.
> >
> > > I think it would be better to still have the FW send the errors and 
> > > kernel
> > > complain about issues with
> > But I agree with this. We should send the ACK.  Luckliy this doesn't 
> > have
> > a long legacy problem because the whole ACK mechanism is a new thing. So
> > we only have to worry about GHESv2 supporting BIOS.
> >
> > -Tony

--
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.