The following commit has been merged into the x86/misc branch of tip:
Commit-ID: a729691b541f6e63043beae72e635635abe5dc09 Gitweb: https://git.kernel.org/tip/a729691b541f6e63043beae72e635635abe5dc09 Author: Paul Gortmaker paul.gortmaker@windriver.com AuthorDate: Sun, 30 May 2021 12:24:47 -04:00 Committer: Thomas Gleixner tglx@linutronix.de CommitterDate: Thu, 12 Aug 2021 12:06:58 +02:00
x86/reboot: Limit Dell Optiplex 990 quirk to early BIOS versions
When this platform was relatively new in November 2011, with early BIOS revisions, a reboot quirk was added in commit 6be30bb7d750 ("x86/reboot: Blacklist Dell OptiPlex 990 known to require PCI reboot")
However, this quirk (and several others) are open-ended to all BIOS versions and left no automatic expiry if/when the system BIOS fixed the issue, meaning that nobody is likely to come along and re-test.
What is really problematic with using PCI reboot as this quirk does, is that it causes this platform to do a full power down, wait one second, and then power back on. This is less than ideal if one is using it for boot testing and/or bisecting kernels when legacy rotating hard disks are installed.
It was only by chance that the quirk was noticed in dmesg - and when disabled it turned out that it wasn't required anymore (BIOS A24), and a default reboot would work fine without the "harshness" of power cycling the machine (and disks) down and up like the PCI reboot does.
Doing a bit more research, it seems that the "newest" BIOS for which the issue was reported[1] was version A06, however Dell[2] seemed to suggest only up to and including version A05, with the A06 having a large number of fixes[3] listed.
As is typical with a new platform, the initial BIOS updates come frequently and then taper off (and in this case, with a revival for CPU CVEs); a search for O990-A<ver>.exe reveals the following dates:
A02 16 Mar 2011 A03 11 May 2011 A06 14 Sep 2011 A07 24 Oct 2011 A10 08 Dec 2011 A14 06 Sep 2012 A16 15 Oct 2012 A18 30 Sep 2013 A19 23 Sep 2015 A20 02 Jun 2017 A23 07 Mar 2018 A24 21 Aug 2018
While it's overkill to flash and test each of the above, it would seem likely that the issue was contained within A0x BIOS versions, given the dates above and the dates of issue reports[4] from distros. So rather than just throw out the quirk entirely, limit the scope to just those early BIOS versions, in case people are still running systems from 2011 with the original as-shipped early A0x BIOS versions.
[1] https://lore.kernel.org/lkml/1320373471-3942-1-git-send-email-trenn@suse.de/ [2] https://www.dell.com/support/kbdoc/en-ca/000131908/linux-based-operating-sys... [3] https://www.dell.com/support/home/en-ca/drivers/driversdetails?driverid=85j1... [4] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/768039
Fixes: 6be30bb7d750 ("x86/reboot: Blacklist Dell OptiPlex 990 known to require PCI reboot") Signed-off-by: Paul Gortmaker paul.gortmaker@windriver.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210530162447.996461-4-paul.gortmaker@windriver.c...
--- arch/x86/kernel/reboot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index ebfb911..0a40df6 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -388,10 +388,11 @@ static const struct dmi_system_id reboot_dmi_table[] __initconst = { }, { /* Handle problems with rebooting on the OptiPlex 990. */ .callback = set_pci_reboot, - .ident = "Dell OptiPlex 990", + .ident = "Dell OptiPlex 990 BIOS A0x", .matches = { DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 990"), + DMI_MATCH(DMI_BIOS_VERSION, "A0"), }, }, { /* Handle problems with rebooting on Dell 300's */