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Subject[PATCH 3/3] 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 I saw the quirk in dmesg - and then disabled
it to find 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 I'm not going 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, I've limited 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.


Fixes: 6be30bb7d750 ("x86/reboot: Blacklist Dell OptiPlex 990 known to require PCI reboot")
Cc: Borislav Petkov <>
Cc: Ingo Molnar <>
Cc: "H. Peter Anvin" <>
Cc: Thomas Renninger <>
Cc: Thomas Gleixner <>
Cc: Rafael J. Wysocki <>
Signed-off-by: Paul Gortmaker <>
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 ebfb91108232..0a40df66a40d 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 = {
{ /* Handle problems with rebooting on Dell 300's */
 \ /
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