From: Matthew Garrett <mjg59@srcf.ucam.org>
To: "Li, Aubrey" <aubrey.li@linux.intel.com>
Cc: "alan@linux.intel.com" <alan@linux.intel.com>,
linux-kernel@vger.kernel.org,
"H. Peter Anvin" <hpa@linux.intel.com>,
Len.Brown@intel.com, Adam Williamson <awilliam@redhat.com>
Subject: Re: [patch] x86: Introduce BOOT_EFI and BOOT_CF9 into the reboot sequence loop
Date: Fri, 28 Feb 2014 04:56:37 +0000 [thread overview]
Message-ID: <20140228045637.GA28257@srcf.ucam.org> (raw)
In-Reply-To: <53100C8D.1060001@linux.intel.com>
On Fri, Feb 28, 2014 at 12:11:57PM +0800, Li, Aubrey wrote:
> This patch is to introduce BOOT_EFI and BOOT_CF9 in the reboot sequence
> loop, to fix the reboot problem on the known Intel Bay Trail-T based
> platform, for example, ASUS-T100 and Dell Venue 8/11 Pro. These
> platforms don't support ACPI reboot, we expect to call EFI runtime
> service to handle this case, and CF9 is an alternate after EFI.
EFI reboot is still somewhat unreliable - it may be safe after the
recent patches to provide a 1:1 mapping. CF9 is, as far as I know, not
part of any spec, so it seems like a bad idea to put it in the default
list.
What do the ACPI reboot vectors look like on these systems?
> - * 3) If still alive, write to the ACPI reboot register again
> - * 4) If still alive, write to the keyboard controller again
> + * 3) If still alive, call EFI runtime service
> + * 4) If still alive, write to the PCI IO port 0xCF9
This is definitely incorrect. The ACPI write *must* occur twice in order
to be effective on various systems. EFI shouldn't be attempted until
after the second ACPI write.
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2014-02-28 4:56 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-28 4:11 [patch] x86: Introduce BOOT_EFI and BOOT_CF9 into the reboot sequence loop Li, Aubrey
2014-02-28 4:56 ` Matthew Garrett [this message]
2014-02-28 5:22 ` Li, Aubrey
2014-02-28 5:56 ` Matthew Garrett
2014-02-28 6:07 ` Li, Aubrey
2014-02-28 6:12 ` Matthew Garrett
2014-02-28 6:20 ` Li, Aubrey
2014-02-28 6:23 ` Matthew Garrett
2014-02-28 6:39 ` Li, Aubrey
2014-02-28 6:44 ` Matthew Garrett
2014-02-28 6:54 ` Li, Aubrey
2014-02-28 17:47 ` H. Peter Anvin
2014-02-28 22:11 ` Li, Aubrey
2014-02-28 22:16 ` Adam Williamson
2014-03-01 17:10 ` Li, Aubrey
2014-03-01 17:22 ` Matthew Garrett
2014-03-01 17:31 ` Li, Aubrey
2014-03-01 18:19 ` Matthew Garrett
2014-03-01 19:01 ` Matthew Garrett
2014-03-02 0:15 ` Li, Aubrey
2014-03-01 20:06 ` H. Peter Anvin
2014-03-01 20:21 ` Matthew Garrett
2014-03-01 20:26 ` H. Peter Anvin
2014-03-02 0:26 ` Li, Aubrey
2014-03-02 0:33 ` H. Peter Anvin
2014-03-02 1:47 ` Li, Aubrey
2014-03-02 2:07 ` H. Peter Anvin
2014-03-02 2:20 ` Li, Aubrey
2014-03-02 2:23 ` Matthew Garrett
2014-03-02 2:35 ` H. Peter Anvin
2014-03-02 10:39 ` Li, Aubrey
2014-03-02 16:52 ` H. Peter Anvin
2014-03-02 22:13 ` Li, Aubrey
2014-03-02 22:26 ` Matthew Garrett
2014-03-02 22:45 ` Li, Aubrey
2014-03-02 23:11 ` Matthew Garrett
2014-03-02 23:23 ` Li, Aubrey
2014-03-03 0:07 ` Matthew Garrett
2014-03-03 0:18 ` H. Peter Anvin
2014-03-03 1:36 ` Li, Aubrey
2014-03-03 1:47 ` H. Peter Anvin
2014-03-03 1:49 ` Li, Aubrey
2014-03-03 22:11 ` Li, Aubrey
2014-03-02 23:57 ` H. Peter Anvin
2014-03-05 23:39 ` [tip:x86/reboot] x86, reboot: Add EFI and CF9 reboot methods into the default list tip-bot for Li, Aubrey
2014-03-05 23:45 ` [tip:x86/reboot] x86, reboot: Only use CF9_COND automatically, not CF9 tip-bot for H. Peter Anvin
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