On 2015-10-06 02:02, Kevin O'Connor wrote:
On Mon, Oct 05, 2015 at 05:04:09PM +0100, edward wandasiewicz wrote:
Following on from this post - http://seabios.seabios.narkive.com/UAt3jVij
I was having the exactly the same problem.
So to summarize, you can boot Linux on Samus, but can not boot any *BSD? Both Linux and the BSDs do work on Link?
[...]
If I run "vbeinfo" within Grub2 on the Pixel 2013, we get a long list, including 640 x 400 and 800 x 600
On the Pixel 2015, "vbeinfo" only gives one entry, and one entry only of 1280 x 850 x 16
Could this explain why *BSD operating systems and MemTest utility cannot boot from USB or SD card (..properly..) ? They boot up in a "text console", versus a "graphical console in text mode".
It's certainly possible that cbvga SeaVGABIOS is the cause. The cbvga support in SeaVGABIOS is a hack to get some minimal display support when only a graphical framebuffer is available. It is known to not work with some bootloaders and OSes (that don't use the VGA BIOS to write to the screen). For that reason, it's not going to work with MemTest86+.
Looks like you have a rom from John Lewis. I'd confirm that the SeaVGABIOS in the rom is relatively recent as there were some changes ("leal" emulation) that are known to work better on the *BSDs.
If SeaVGABIOS is recent, then I think the next step would be to see if you can replace SeaVGABIOS with an Intel VGABIOS.
I'm not absolutely sure how old it is, but I don't think it's any older than 2 or 3 weeks, since that was the last time I really had a bash at getting this working properly, and I finished up by putting the cbvga option ROM in. I guess what this points to is that I should get the script, run by Jenkins, to update the cbvga option ROM every time, if I'm going to continue running that way.
If I disable coreboot framebuffer support in SeaBIOS and then use the VGABIOS from the stock ROM in RW_LEGACY, I don't get any display from SeaBIOS on Broadwell.
If I do the same with a Haswell Chromebook, the display works.
In the former case, SeaBIOS appears to find and load the VGABIOS, according to cbmem, just no display.
I think whatever this problem is may also explain why I'm not able to get display using a modified BOOT_STUB with SeaBIOS on Broadwell.
Another thing that may or may not have some bearing is that on Baytrail, if I try to use RW_LEGACY with SeaBIOS, SeaBIOS initialises the display, but Linux won't display anything unless I disable KMS with "nomodeset" on the kernel cmdline. That unfortunately leaves me with a display resolution of 1024x768 (presumably what coreboot sets the framebuffer to).
If you have some stuff I can try to get a VGABIOS working properly with BOOT_STUB and RW_LEGACY on Broadwell and Baytrail Chromebooks, I would sure appreciate it, Kevin.
-John.
-Kevin
P.S. it should be possible to implement a SeaVGABIOS with support for mode switching on Intel graphics adapters. That should solve these problems (at least on Intel hardware), but it's a bit of work as I find the Intel graphics manuals to be basically indecipherable. :-(