[coreboot] coreboot+seabios timings

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Mon Oct 18 05:56:27 CEST 2010

On 18.10.2010 05:46, Stefan Reinauer wrote:
>  On 10/17/10 7:54 PM, Scott Duplichan wrote:
>> Thanks. I had already noticed the double KB init and turned off the
>> coreboot instance.
> Should we add a "use SeaBIOS as payload" option that disables all that
> stuff automatically?

Given that the issue crops up very often, I think this would be a major
usability improvement. I'd even go as far as defaulting it to yes.

>>  I switched to seabios execution of video option 
>> roms and found an immediate improvement. Before, I had a problem adding
>> a PCI video card. It seems like coreboot would execute the uma option
>> rom instead of the PCI option rom. After changing to seabios execution 
>> of option roms, it now works correctly. I can boot either uma video or
>> pci video without changing my image. I probably need to get an SSD drive
>> at this point. I found with the drive already spinning, boot time is 
>> around 1.70 seconds. However I remembered a 40 ms delay inside the PCIe
>> training loop. I had removed it to speed up simnow execution. With the
>> delay restored, boot time goes up by 270 ms or so. That delay needs some
>> optimization. I see it is called even for non-existent PCIe devices.
> Do we need to think about cooperative multitasking?

It would help a lot with SATA link init. That is the biggest time waster
(few seconds) on my RS690/SB600 box because apparently my HDD only
completes link init after spinup. Kicking it early and polling for it
very late would allow coreboot to do something useful in between.

Being able to register a callback which is called directly before
payload execution would be the simplest way to do this.



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