Re: [GIT PULL] Workaround for broken Geode E820 BIOS

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



I just tried 2.6.23-rc8 with the patch applied. Works fine here, so my very first

Acked-by: Joerg Pommnitz <[email protected]>

for whatever it's worth, since it is already in Linus' tree.

Thanks to  Peter and Jordan  for  taking the interest and time to track
this one down and fix it. 

--  
Regards
 
       Joerg
 


----- Ursprüngliche Mail ----
Von: H. Peter Anvin <[email protected]>
An: Linus Torvalds <[email protected]>
CC: Linux Kernel Mailing List <[email protected]>; Jordan Crouse <[email protected]>; Joerg Pommnitz <[email protected]>
Gesendet: Donnerstag, den 27. September 2007, 00:27:20 Uhr
Betreff: [GIT PULL] Workaround for broken Geode E820 BIOS

Hi Linus,

Please pull:

  git://git.kernel.org/pub/scm/linux/kernel/git/hpa/linux-2.6-x86setup.git for-linus

H. Peter Anvin (1):
      [x86 setup] Handle case of improperly terminated E820 chain

 arch/i386/boot/memory.c |   30 +++++++++++++++++++++++-------
 1 files changed, 23 insertions(+), 7 deletions(-)

[Log messages and full diffs follow]

commit 2efa33f81ef56e7700c09a3d8a881c96692149e5
Author: H. Peter Anvin <[email protected]>
Date:   Wed Sep 26 14:11:43 2007 -0700

    [x86 setup] Handle case of improperly terminated E820 chain
    
    At least one system (a Geode system with a Digital Logic BIOS) has
    been found which suddenly stops reporting the SMAP signature when
    reading the E820 memory chain.  We can't know what, exactly, broke in
    the BIOS, so if we detect this situation, declare the E820 data
    unusable and fall back to E801.
    
    Also, revert to original behavior of always probing all memory
    methods; that way all the memory information is available to the
    kernel.
    
    Signed-off-by: H. Peter Anvin <[email protected]>
    Cc: Jordan Crouse <[email protected]>
    Cc: Joerg Pommnitz <[email protected]>

diff --git a/arch/i386/boot/memory.c b/arch/i386/boot/memory.c
index 1a2e62d..bccaa1c 100644
--- a/arch/i386/boot/memory.c
+++ b/arch/i386/boot/memory.c
@@ -20,6 +20,7 @@
 
 static int detect_memory_e820(void)
 {
+    int count = 0;
     u32 next = 0;
     u32 size, id;
     u8 err;
@@ -33,14 +34,24 @@ static int detect_memory_e820(void)
               "=m" (*desc)
             : "D" (desc), "a" (0xe820));
 
-        if (err || id != SMAP)
+        /* 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;
+        }
 
-        boot_params.e820_entries++;
+        if (err)
+            break;
+
+        count++;
         desc++;
-    } while (next && boot_params.e820_entries < E820MAX);
+    } while (next && count < E820MAX);
 
-    return boot_params.e820_entries;
+    return boot_params.e820_entries = count;
 }
 
 static int detect_memory_e801(void)
@@ -89,11 +100,16 @@ static int detect_memory_88(void)
 
 int detect_memory(void)
 {
+    int err = -1;
+
     if (detect_memory_e820() > 0)
-        return 0;
+        err = 0;
 
     if (!detect_memory_e801())
-        return 0;
+        err = 0;
+
+    if (!detect_memory_88())
+        err = 0;
 
-    return detect_memory_88();
+    return err;
 }






      Die etwas anderen Infos rund um das Thema Reisen. BE A BETTER WELTENBUMMLER!  www.yahoo.de/clever
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux