David Weinhall wrote: > On Tue, Dec 19, 2000 at 07:16:40PM -0500, Marc Joosen wrote: > > > > This is a tiny patch to make the int15/e820 memory mapping work on IBM > > ThinkPads. Until now, I have had to give lilo a mem= option with one meg > > If this simple patch solves your problem, great! But in that case, > PLEASE add a note telling WHY the assignment is done for every > iteration; else some smarthead will probably submit a patch someday > in the future along the lines of "assigning this only once makes the > loop faster"... > > Anyhow, good spotting! Thanks for the tip, David. I hope that whoever wants to move that line out of the loop is aware that it is only executed ~10 times :) So I hereby submit a second version of the patch, that includes a link to the documentation and #defines the word SMAP (thanks to David Parsons for that): --- linux/arch/i386/boot/setup.S.orig Mon Oct 30 17:44:29 2000 +++ linux/arch/i386/boot/setup.S Thu Dec 21 19:37:12 2000 @@ -289,10 +289,11 @@ # a whole bunch of different types, and allows memory holes and # everything. We scan through this memory map and build a list # of the first 32 memory areas, which we return at [E820MAP]. -# +# This is documented at http://www.teleport.com/~acpi/acpihtml/topic245.htm + +#define SMAP 0x534d4150 meme820: - movl $0x534d4150, %edx # ascii `SMAP' xorl %ebx, %ebx # continuation counter movw $E820MAP, %di # point into the whitelist # so we can have the bios @@ -300,13 +301,15 @@ jmpe820: movl $0x0000e820, %eax # e820, upper word zeroed + movl $SMAP, %edx # do this every time, some + # bioses are forgetful movl $20, %ecx # size of the e820rec pushw %ds # data record. popw %es int $0x15 # make the call jc bail820 # fall to e801 if it fails - cmpl $0x534d4150, %eax # check the return is `SMAP' + cmpl $SMAP, %eax # check the return is `SMAP' jne bail820 # fall to e801 if it fails # cmpl $1, 16(%di) # is this usable memory? Again, please copy any comments to me ([EMAIL PROTECTED]), since I'm not subscribed to linux-kernel. -- Marc Joosen Communication Link Design IBM T.J. Watson Research Center Yorktown Heights, NY - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
