Re: [PATCH] x86: Reserve legacy VGA MMIO area for x86_64 as wellas x86_32

From: H. Peter Anvin
Date: Wed Apr 07 2010 - 19:44:37 EST

On 04/07/2010 03:45 PM, Yinghai wrote:
> It seem another thread, erission has one model without VGA, and they use that area for other device MMIO.
> current for 64bit, We remove [0xa0000, 0x100000) from e820 map if those area is E820_RAM.

Removing is not the same thing as reserving!

A range with no type in E820 is address space available for allocation;
whereas in order to be reserved, it should be E820_RESERVED.

> in e820_reserve_resources(), kernel will reserve range < 1M according to e820 map.
> that is before pci BAR is claimed.
> or you can add
> boot_params.screen_info.orig_video_isVGA == 1
> or double check scan pci tree to see if video is there or not

Perhaps boot_params.screen_info.orig_video_isVGA != 1 because he's not
booting in a text mode?


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