From: Thomas Gleixner <tglx@linutronix.de>
To: Maximilian Luz <luzmaximilian@gmail.com>,
David Laight <David.Laight@ACULAB.COM>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Sachi King <nakato@nakato.io>,
"x86\@kernel.org" <x86@kernel.org>,
"linux-kernel\@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"stable\@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH] x86/i8259: Work around buggy legacy PIC
Date: Fri, 14 May 2021 15:44:57 +0200 [thread overview]
Message-ID: <87r1i94eg6.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <e7dbd4d1-f23f-42f0-e912-032ba32f9ec8@gmail.com>
Max,
On Thu, May 13 2021 at 12:11, Maximilian Luz wrote:
> And lastly, if that's any help at all: The PIC device is described in
> ACPI in [3]. The Surface Laptop 3 also has an AMD CPU (although a prior
> generation) and has the PIC described in the exact same way (can also be
> found in that repository), but doesn't exhibit that behavior (and
> doesn't show the "Using NULL legacy PIC" line). I expect there's not
> much you can change to that definition so that's probably irrelevant
> here.
>
> Again, I don't really know anything about these devices, so my guess
> would be bad hardware revision or bad firmware revision. All I know is
> that retrying seems to "fix" it.
That might be a a power optimization thing.
Except for older systems the PIC is not really required for IOAPiC to
work. But there is some historical code which makes assumptions. We can
change that, but that needs some careful thoughts.
Thanks,
tglx
next prev parent reply other threads:[~2021-05-14 13:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-12 21:04 [PATCH] x86/i8259: Work around buggy legacy PIC Maximilian Luz
2021-05-13 8:10 ` David Laight
2021-05-13 10:11 ` Maximilian Luz
2021-05-13 10:36 ` David Laight
2021-05-14 13:01 ` Thomas Gleixner
2021-05-14 13:13 ` David Laight
2021-05-14 16:19 ` Ingo Molnar
2021-05-14 19:41 ` Sachi King
2021-05-14 10:51 ` David Laight
2021-05-14 11:58 ` Maximilian Luz
2021-05-14 17:32 ` Thomas Gleixner
2021-05-14 17:35 ` H. Peter Anvin
2021-05-14 22:47 ` Maximilian Luz
2021-05-17 18:40 ` Thomas Gleixner
2021-05-17 19:25 ` Maximilian Luz
2021-05-17 23:27 ` Thomas Gleixner
2021-05-18 8:28 ` Andy Shevchenko
2021-05-18 19:58 ` Sachi King
2021-05-18 15:45 ` Thomas Gleixner
2021-05-14 13:44 ` Thomas Gleixner [this message]
2021-05-14 16:12 ` David Laight
2021-05-14 17:28 ` H. Peter Anvin
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