[PATCH -mm] clocksource: add PM Timer bug hunting notes

[Andreas Mohr]

On Tue, Jun 20, 2006 at 05:16:58PM +0200, Andreas Mohr wrote:
> Hi,
> 
> On Tue, Jun 20, 2006 at 11:58:01PM +0900, OGAWA Hirofumi wrote:
> > Almost ICH4 should be sane.  Since there seems both reports of good
> > and bad, probably the bug of ICH4 seems to be depending on a specific
> > motherboard.
> > 
> > FWIW, If you want to reduce gray-list, probably it should be
> > motherboard list.
> 
> OK, so if I get a nice description of which dual P4 Xeon motherboard that
> was (Dell something?), then I'll make a patch adding
> this chipset's revision + motherboard + LKML link of bug test app
> to the file, and asking for more testers there, too.

Done, hope that's ok (fixed a typo in the process).

Jean-Daniel, Chris: please complain loudly if you don't want to have your name
in that file...

Compile-tested on 2.6.17-mm1.

Signed-off-by: Andreas Mohr <andi@xxxxxxxx>


--- linux-2.6.17-mm1.orig/drivers/clocksource/acpi_pm.c	2006-06-21 14:28:16.000000000 +0200
+++ linux-2.6.17-mm1/drivers/clocksource/acpi_pm.c	2006-06-23 20:11:32.000000000 +0200
@@ -70,7 +70,7 @@
 	.rating		= 200,
 	.read		= acpi_pm_read,
 	.mask		= (cycle_t)ACPI_PM_MASK,
-	.mult		= 0, /*to be caluclated*/
+	.mult		= 0, /* to be calculated */
 	.shift		= 22,
 	.is_continuous	= 1,
 };
@@ -92,7 +92,8 @@
 }
 
 /*
- * PIIX4 Errata:
+ * PIIX4 Errata #20, Intel PDF 29773817:
+ * (affects PIIX4 A0/A1/B0 and PIIX4E A0, *fixed* in PIIX4M A0)
  *
  * The power management timer may return improper results when read.
  * Although the timer value settles properly after incrementing,
@@ -135,6 +136,20 @@
 	       " workaround\n");
 
 	acpi_pm_need_workaround();
+
+	/* If you happen to have such a chipset and want to help improve things,
+	   then please run OGAWA Hirofumi's test app at
+	   http://marc.theaimsgroup.com/?l=linux-kernel&m=114297656924494&w=2
+	   (run for a somewhat longer time to be sure)
+	   and report bug status of your chipset revision/motherboard.
+
+	   Devices that seem to work fine (run "lspci -n"):
+	   - Chris Rankin: 8086:24c0 (rev 01), Dell Precision 650 (dual P4 Xeon)
+	   - Jean-Daniel Pauget: 8086:24c0 (rev 02), ASUS P4PE (non-SMP)
+
+	   Possibly the 8086:24c0 device is completely fine with all revisions
+	   after all... (but not sure yet, which is why we need your input)
+	*/
 }
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82801DB_0,
 			acpi_pm_check_graylist);

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