[lkml]   [2005]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [RFC] Reliable video POSTing on resume (was: Re: [ACPI] Samsung P35, S3, black screen (radeon))
    Pavel Machek <> writes:

    > Hi!
    > > > We already try to do that, but it hangs on 70% of machines. See
    > > > Documentation/power/video.txt.
    > >
    > > We know that all of these ROMs are run at power on so they have to
    > > work. This implies that there must be something wrong with the
    > > environment the ROM are being run in. Video ROMs make calls into the
    > > INT vectors of the system BIOS. If these haven't been set up yet
    > > running the VBIOS is sure to hang. Has someone with ROM source and
    > > the appropriate debugging tools tried to debug one of these hangs?
    > > Alternatively code could be added to wakeup.S to try and set these up
    > > or dump the ones that are there and see if they are sane.
    > Rumors say that notebooks no longer have video bios at C000h:0; rumors
    > say that video BIOS on notebooks is simply integrated into main system
    > BIOS. I personaly do not know if rumors are true, but PCs are ugly
    > machines....

    The state of current hardware has already been mentioned but let
    me clarify. This is not a laptop problem anytime you have onboard
    video you are unlikely to have a separate video ROM. This includes
    many recent server boards as well as laptops. When the board boots
    up there will be a video option ROM shadowed into the usually location
    at C000h:0 but what becomes of it afterwards is a good question.

    For server boards most commonly this seems to be a flavor of the ATI
    Rage XL chip. It is a low end part that I doubt getting documentation
    for will be very hard. And according to
    Documentation/power/video.txt this is one of the cases that actually

    What is happening in those POST routines of a video card is typically
    the code to initialize the memory controller on the video card. Plus
    a little bit of code to set the video mode. If I read the
    documentation correctly in a S3 power state only the RAM is preserved.
    So it does look like the video post is needed.

    Hmm. Looking at the ACPI 3.0 spec it appears there is a _ROM method
    that can be called to get a copy of the ROM image for an onboard
    video card. Has any one tried that method?


    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 14:10    [W:0.021 / U:3.220 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site