44 lines
1.8 KiB
Plaintext
44 lines
1.8 KiB
Plaintext
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Video issues with S3 resume
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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2003-2004, Pavel Machek
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During S3 resume, hardware needs to be reinitialized. For most
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devices, this is easy, and kernel driver knows how to do
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it. Unfortunately there's one exception: video card. Those are usually
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initialized by BIOS, and kernel does not have enough information to
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boot video card. (Kernel usually does not even contain video card
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driver -- vesafb and vgacon are widely used).
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This is not problem for swsusp, because during swsusp resume, BIOS is
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run normally so video card is normally initialized.
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There are three types of systems where video works after S3 resume:
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* systems where video state is preserved over S3. (Athlon HP Omnibook xe3s)
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* systems where it is possible to call video bios during S3
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resume. Unfortunately, it is not correct to call video BIOS at that
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point, but it happens to work on some machines. Use
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acpi_sleep=s3_bios (Athlon64 desktop system)
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* systems that initialize video card into vga text mode and where BIOS
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works well enough to be able to set video mode. Use
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acpi_sleep=s3_mode on these. (Toshiba 4030cdt)
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* on some systems s3_bios kicks video into text mode, and
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acpi_sleep=s3_bios,s3_mode is needed (Toshiba Satellite P10-554)
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* radeon systems, where X can soft-boot your video card. You'll need
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patched X, and plain text console (no vesafb or radeonfb), see
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http://www.doesi.gmxhome.de/linux/tm800s3/s3.html. (Acer TM 800)
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Now, if you pass acpi_sleep=something, and it does not work with your
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bios, you'll get hard crash during resume. Be carefull.
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You may have system where none of above works. At that point you
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either invent another ugly hack that works, or write proper driver for
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your video card (good luck getting docs :-(). Maybe suspending from X
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(proper X, knowing your hardware, not XF68_FBcon) might have better
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chance of working.
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