lkml.org 
[lkml]   [2005]   [Feb]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RFC] Reliable video POSTing on resume
    On Sat, 05 Feb 2005 02:17:22 +0000, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
    > On laptops, it's frequently the case that c000:0003 will jump to a
    > section of code that is no longer mapped into the address space.
    > Instead, it's entirely possible that some other section of BIOS will be
    > mapped there. The resulting behaviour is undefined, and can cause the
    > hardware to hang.

    I suspect the problem in that case is a compressed VBIOS. Some laptops
    compress the VBIOS and the system BIOS into a single ROM and then
    expand them at power on. Sounds like this is not happening on resume.
    To get around the problem copy the image from C000:0 before suspend to
    a place in preserved RAM where wakeup.S can find it and then copy it
    back to C000:0 on resume. To test for this checksum C000:0 before
    suspend and after and see if it has changed.

    You can always do a simple test. If a program like vbios.vm86 or
    vbetool can reset the card, then there is no reason wakeup.S shouldn't
    be able to do it too if the environment is set up correctly.

    --
    Jon Smirl
    jonsmirl@gmail.com
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 14:10    [W:0.022 / U:29.996 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site