Bug 13253

Summary:	x86_64 kernel misinterprets "reserve=" boot parameter
Product:	ACPI	Reporter:	pablomme (pablomme)
Component:	Config-Other	Assignee:	Zhang Rui (rui.zhang)
Status:	CLOSED CODE_FIX
Severity:	normal	CC:	keng-yu.lin, lenb, randy.dunlap
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.28	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	dmesg with reserve parameter set on x86_64 patch: io_start use unsigned int intead of int

Description pablomme 2009-05-06 01:43:03 UTC

I've reported this on Ubuntu Launchpad as bug 370003, but it seemed wise to report it here as well.

My laptop suffers from bug #9905 (#187671 in launchpad), which is in fact a BIOS defect: the ACPI tables suggest an arrangement where MMIO regions for different devices overlap and cause the machine to freeze on loading the sdhci[-pci] module, as well as the vanilla 8139too module (the latter was modified a while back in Ubuntu to use PIO instead, to partially address this problem).

Recently another user reported successfully bypassing the problem by adding "reserve=0xffb00000,0x100000" to the kernel command line. I can confirm this works on the x86 kernel, but not on the x86_64 kernel, which I'm currently running.

When adding the option to the x86_64 kernel, /proc/iomem shows this as the last line:

ffffffffffb00000-ffffffffffbfffff : reserved

which should have been, clearly, one of:

ffb00000-ffbfffff : reserved
00000000ffb00000-00000000ffbfffff : reserved

but for some reason the kernel prepends a bunch of ones instead of zeros to the 32-bit address to produce a 64-bit address. Specifying "reserve=0x00000000ffb00000,0x100000" on the command line does not help, though.

Let me know if I've misclassified the bug, my guess is ACPI, but I may be very wrong here...

Comment 1 Zhang Rui 2009-05-20 03:44:46 UTC

please attach the full dmesg ouput after boot.

Comment 2 pablomme 2009-05-20 18:19:16 UTC

Created attachment 21457 [details]
dmesg with reserve parameter set on x86_64

Attached. I can also produce dmesgs without using "reserve", and for the 32-bit kernel using an Ubuntu liveCD, if any of these help.

Comment 3 Zhang Rui 2009-06-02 06:58:33 UTC

Created attachment 21703 [details]
patch: io_start use unsigned int intead of int

please re-open this bug if the patch doesn't work for you.

Comment 4 Zhang Rui 2009-06-02 07:11:55 UTC

patch is also sent to the ACPI mail list.
http://patchwork.kernel.org/patch/27403/

Comment 5 pablomme 2009-06-03 00:45:47 UTC

Works beautifully, thanks.

Comment 6 Len Brown 2009-08-29 18:58:19 UTC

8bc1ad7dd301b7ca7454013519fa92e8c53655ff
kernel/resource.c: fix sign extension in reserve_setup()
shipped in linux-2.6.31-rc2

closed.