Re: More E820 brokenness

[H. Peter Anvin]

Jordan Crouse wrote:
> On 27/09/07 15:47 -0700, H. Peter Anvin wrote:
>> Jordan Crouse wrote:
>>> Breaks on the Geode - original behavior.
>>>
>>> I think that having boot_prams.e820_entries != 0 makes the kernel
>>> assume the e820 data is correct.
>>>
>> Okay, now I'm utterly baffled how 2.6.22 ever worked on this Geode,
>> because this, to the best of my reading, mimics the 2.6.22 behavior
>> exactly.  DID IT REALLY, and/or did you make any kind of configuration
>> changes?
> 
> I copied in a 2.6.22 kernel to see that it really did work, and it did.
> But here's the crazy part - I did a dmesg, and it looks like it
> *is* using e820 data, and it looks complete (I see the entire map - 
> including the ACPI and reserved blocks way up high).
> 
> So apparently it was the 2.6.22 code that was buggy, but reading it,
> I don't immediately see how. 
> 

Oh bugger, looks like this one might be genuinely my fault after all.
The ID check in the new code is buggy.

Can you please test this revised patch out (against current -git)?

	-hpa



diff --git a/arch/i386/boot/memory.c b/arch/i386/boot/memory.c
index bccaa1c..84939b7 100644
--- a/arch/i386/boot/memory.c
+++ b/arch/i386/boot/memory.c
@@ -34,17 +34,7 @@ static int detect_memory_e820(void)
 		      "=m" (*desc)
 		    : "D" (desc), "a" (0xe820));
 
-		/* Some BIOSes stop returning SMAP in the middle of
-		   the search loop.  We don't know exactly how the BIOS
-		   screwed up the map at that point, we might have a
-		   partial map, the full map, or complete garbage, so
-		   just return failure. */
-		if (id != SMAP) {
-			count = 0;
-			break;
-		}
-
-		if (err)
+		if (id != SMAP || err)
 			break;
 
 		count++;