Messages in this thread | | | Date | Sat, 6 Sep 2008 14:07:20 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] Ghost EDD devices in /sys again |
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* Andrey Borzenkov <arvidjaar@newmail.ru> wrote:
> On Friday 05 September 2008, Andrey Borzenkov wrote: > > This is regression but old enough. Apparently I had for whatever reasons > > EDD turned off till recently. This is 2.6.27-rc5 just in case. > > > > In 2006 I fixed ghost devices due to buggy BIOS: > > > > http://marc.info/?l=linux-kernel&m=114087765422490&w=2 > > > > Later edd.S has been rewritten in C, and apparently this patch has been > > lost: > > > > {pts/1}% ls /sys/firmware/edd > > int13_dev80/ int13_dev84/ int13_dev88/ int13_dev8c/ > > int13_dev81/ int13_dev85/ int13_dev89/ int13_dev8d/ > > int13_dev82/ int13_dev86/ int13_dev8a/ int13_dev8e/ > > int13_dev83/ int13_dev87/ int13_dev8b/ int13_dev8f/ > > > > But I have just a single disk. This is the same system BTW. > > > > Unfortunately I do not speak asm language of C; if somebody could provide > > equivalent fix for current edd.c, I am more than ready to test it. > > Was it really that simple? > > Subject: [PATCH] Fix ghost devices under /sys/firmware/edd > From: Andrey Borzenkov <arvidjaar@mail.ru> > > Some BIOSes do not always set CF on error before return from int13. > The patch adds additional check for status being zero (AH == 0). > > This was fixed for edd.S in > http://marc.info/?l=linux-kernel&m=114087765422490&w=2, but lost > again when edd.S was rewritten in C. > > Signed-off-by: Andrey Borzenkov <arvidjaar@mail.ru> > > --- > > arch/x86/boot/edd.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > > diff --git a/arch/x86/boot/edd.c b/arch/x86/boot/edd.c > index d93cbc6..bf4ae6f 100644 > --- a/arch/x86/boot/edd.c > +++ b/arch/x86/boot/edd.c > @@ -32,7 +32,9 @@ static int read_mbr(u8 devno, void *buf) > : "+a" (ax), "+c" (cx), "+d" (dx), "+b" (bx) > : : "esi", "edi", "memory"); > > - return -(u8)ax; /* 0 or -1 */ > + /* Some BIOSes do not set carry flag on error but still return > + * error in AH. The condition below is expected to catch both */ > + return -!!ax; /* 0 or -1 */ > } > > static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig)
looks good to me - applied it to tip/x86/urgent. Thanks Andrey!
Ingo
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