Re: [patches] [PATCH] [21/22] x86_64: Extend bzImage protocol for relocatable bzImage

[ebiederm@xmission.com (Eric W. Biederman)]

"H. Peter Anvin" <hpa@zytor.com> writes:

> yhlu wrote:
>> so the kexec tools need to scan the pci devices list, and find out how
>> to set real_mode.isVGA and orig_video_mode, also need to parse the
>> comand line about vga console.
>
> BTW, welcome to the hell of bypassing setup.

Well in this case things are so very much better then attempting to
us setup.S it isn't a real option.

In general BIOS calls just don't work reliably after linux has
been running for a while.

As for YH's point it does look like there are a few ways
to poke the linux kernel to see what is happening.

We can look in /proc/ioports and see what has reserved
the video resources.  That should give us a reasonable
estimate of the video adapter.  We can do an ioctl to
the console and see how many lines and columns we have.

Reusing boot_params could be nice but if we have the information
available in other ways digging it out that way is quite possibly
better.


Eric
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