[lkml]   [2011]   [Jan]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic
    On Tue, 2011-01-25 at 17:36 +0200, Ahmed S. Darwish wrote:
    > The complete __roadblock__ I'm currently facing though is restoring the disk
    > controllers to the state originally setup by the BIOS Power-on self-test (POST).
    > I hope such re-initialization is even technically feasible.
    > Without such re-initialization, we'll just be risking the BIOS code exploding.
    > That was the case in the 5-minute hang described in the cover sheet (PATCH #0).

    So this is the bit that's not really technically feasible. BIOS tends
    to run storage devices in a very primitive way (so it takes basic
    settings, for example and sets the device up for one particular channel
    of access). When preparing the device for an operating system, we have
    to blow away all the bios stuff and put it into a more generally
    performant mode (this isn't just the storage per se, it's also the
    interrupt and routing). Unfortunately, currently, we don't bother to
    save the settings the BIOS was using, so there's no way to reinitialise
    the device back to bios without an effective reboot. Most BIOS doesn't
    seem to contain storage re-POST code that's usable (it's all embedded in
    the boot sequence).


     \ /
      Last update: 2011-01-25 17:05    [from the cache]
    ©2003-2014 Jasper Spaans. hosted at Digital Ocean