Red Hat Bugzilla – Bug 55224
GRUB 0.90 bootloader confuses Windows APM driver
Last modified: 2008-05-01 11:38:01 EDT
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.5) Gecko/20011012 Description of problem: There is APM detection code in the GRUB bootloader version 0.90 which leaves it in an inconsistent state before booting, and this confuses the Windows APM driver, therefore disabling it. I have not tested it on every machine/Windows combination, but on my machines it is entirely reproducible. In any case, the code was incorrect. I debugged this for the GRUB folks (I am the original author getting back into the development again), and thought you might like the patch, included below... I don't know if you follow the development list. You may even want to grab the 0.91 version that's coming out in a few days/week. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1. Install RH 7.2 on a system with Windows (98/ME) installed. 2. Boot into Windows. 3. Note that in the "System" control panel, the Advanced Power Management driver is marked as not functioning. Additional info: -------------------------(start patch here)----------------------- --- grub.orig/stage2/apm.S Tue Oct 24 23:16:16 2000 +++ grub/stage2/apm.S Fri Oct 26 11:45:04 2001 @@ -91,12 +91,12 @@ xorw %cx, %cx int $0x15 /* error -> should not happen, tidy up */ - jc apm_disconnect + jc done_apm_bios /* check for "PM" signature */ cmpw $0x504d, %bx /* no signature -> should not happen, tidy up */ - jne apm_disconnect + jne done_apm_bios /* record the APM BIOS version */ movw %ax, ABS(EXT_C(apm_bios_info)) @@ -104,19 +104,17 @@ movw %cx, ABS(EXT_C(apm_bios_info)) + 12 jmp done_apm_bios -apm_disconnect: - /* Disconnect */ - movw $0x5304, %ax - xorw %bx, %bx - /* ignore return code */ - int $0x15 - jmp done_apm_bios - no_32_apm_bios: /* remove 32 bit support bit */ andw $0xfffd, ABS(EXT_C(apm_bios_info)) + 12 done_apm_bios: + /* Some paranoia here: Always Disconnect from APM */ + movw $0x5304, %ax + xorw %bx, %bx + /* ignore return code */ + int $0x15 + DATA32 call EXT_C(real_to_prot) .code32 -------------------------(end patch here)-----------------------
Yep, I grabbed the patch off of the list yesterday and have a test package up at http://people.redhat.com/~katzj/RPMS/grub-0.90-12.i386.rpm... waiting for confirmation from the other filed bugs that this fixes the problem. *** This bug has been marked as a duplicate of 54375 ***
Err, I just tried your RPM, and it hung my test system! (a Pentium 4 machine) Hmm. In trying to isolate this a bit further, it seems that all of them including your new one runs fine from a floppy. Further, the problem existed when I changed back to the old version of GRUB, but it worked with the original install from the CD obviously. It *does* work with a stage2 from the CVS version of GRUB. Argh, I found the problem. You're going to absolutely *love* this (not)... the problem is that the disk cache is incoherent with the raw device!!!! So, when "grub-install" copies the stage2 over, Ext3 hasn't updated all of it's state enough so that the raw device reflects it. The *real* problem is that there was no "sync" command in the "grub-install" script in places where the grub shell was being called. I am posting a patch to the "bug-grub" list momentarily... But, after that patch, all works well. ;-)