Re: About the reboot hang issue with EHCI driver on the Baytrail platform

[Alan Stern]

On Wed, 27 Aug 2014, Gavin Guo wrote:

> > Still, why not use the BIOS setting to disable EHCI?
> 
> It's hardware enablement policy. By default, we can't change the BIOS
> setting to make the bug disappear until we find out the bug is due to
> BIOS's bug. Add kernel parameters is the temporary solution for the
> platform can ship. And if the bug is from kernel, we need to send
> patches to upstream and pull back to Ubuntu kernel or send to Ubuntu
> Kernel directly if it's a trivial solution like adding device id.
> However, as you said, in this case about the bug the root may be from
> BIOS code. So, we can coordinate with the OEM BIOS team to modify the
> default BIOS setting.

There is no doubt that the BIOS is buggy.  Your log contains this line:

[    2.804205] pci 0000:00:1d.0: EHCI: BIOS handoff failed (BIOS bug?) 01010001

The only way that can happen is if the BIOS isn't working right. 
However, this may be a different bug from the crashes you've been 
seeing.

Alan Stern

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