Re: grub2 code

[Ben Guthro]

On Mon, Feb 3, 2014 at 6:57 AM, Colin Watson <address@hidden> wrote:
> On Sun, Feb 02, 2014 at 07:25:51PM +0000, Robert Parnell wrote:
>> I was just looking at the grub2 source code and saw that
>> https://bazaar.launchpad.net/~ubuntu-branches/ubuntu/trusty/grub2/trusty/view/head:/TODO
>> <https://bazaar.launchpad.net/%7Eubuntu-branches/ubuntu/trusty/grub2/trusty/view/head:/TODO>
>> says to contact with questions.
>> I was looking at the source because I encountered a bug on my machine
>> that has been previously reported
>> (https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1027694) and
>> thought I'd have a look to see if I could find the problem.
>> So I have 2 questions:
>> 1. Is the code on launchpad the up to date code?
>
> It's an automatically-imported version of the Ubuntu packaging.  It's
> up-to-date with what we're shipping, yes, but we do our work in git
> these days.  The upstream code is here:
>
>   http://git.savannah.gnu.org/gitweb/?p=grub.git
>
> ... and the packaging used by both Debian and Ubuntu is here (the
> "experimental" branch is most current):
>
>   http://anonscm.debian.org/gitweb/?p=pkg-grub/grub.git
>
>> 2. Line 177 of
>> https://bazaar.launchpad.net/~ubuntu-branches/ubuntu/trusty/grub2/trusty/view/head:/grub-core/boot/i386/pc/startup_raw.S
>> <https://bazaar.launchpad.net/%7Eubuntu-branches/ubuntu/trusty/grub2/trusty/view/head:/grub-core/boot/i386/pc/startup_raw.S>
>> is a function that flushes the keyboard buffer, could this be what is
>> causing the bug?
>
> That seems unrelated.
>
> Ben's patch referenced in https://savannah.gnu.org/bugs/?34547 touches
> code that I wrote and that I maintain as a patch, so this would
> presumably be my problem to fix.  But I don't understand why Ben's patch
> fixes anything related to NumLock.  The code being commented out is
> essentially:
>
>         movw    $(GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR + 0x17), %bx
>         andb    $3, (%bx)
>
> ... followed by something that tests the condition flags.  But all that
> does is test whether either Shift key is held down, not actually set the
> NumLock state (see http://www.bioscentral.com/misc/bda.htm).  That is,
> it reads from the BIOS Data Area, but it doesn't write to it.
>
> Ben (CCed), could you shed some light on why your patch would fix this?

Adding Roger Cruz, as he was the original author of this fix, where I
was just trying to get it upstreamed - though, this was quite some
time since he developed it (Oct 2011), so I'm sure this isn't exactly
fresh in his mind.

Roger, could you shed some light on  this?

Ben

>
> Thanks,
>
> --
> Colin Watson                                       address@hidden