CC: Luigi, he works at Google and is responsible for the TPMs in Chromebooks ;)
Thanks, Peter Am Freitag, 22. August 2014, 22:32:41 schrieb Jason Gunthorpe: > On Fri, Aug 22, 2014 at 08:17:27PM +0000, Scot Doyle wrote: > > On Fri, 22 Aug 2014, Jason Gunthorpe wrote: > > > On Fri, Aug 22, 2014 at 12:58:41AM +0000, Scot Doyle wrote: > > >> Some machines, such as the Acer C720 and Toshiba CB35, have TPMs > > >> that do not use interrupts while also having an ACPI TPM entry > > > > > > How do these machines work in Windows? > > > > I don't know. Since they're Chromebooks (booted in legacy mode running > > SeaBIOS instead of depthcharge or whatever ChromeOS uses), I think > > they're mostly used to run Linux. > > I remain somewhat confused - there have already been TPM patches for > Chromebooks from Google - presumably the TPM actually does work > fine. Make sure you are using a Linux with the ATMEL timeout fix, that > is particularly applicable to Chromebooks IIRC. > > And again, the driver uses interrupts when booting, so I'm somewhat > confused what the problem is. I wouldn't think the driver would > successfully attach if interrupts were enabled but the interrupt > didn't work? Can you elaborate on what is going on during boot with > the interrupt, and the boot time GET_DURATIONS and TPM_STARTUP > sequences? > > Perhaps the driver is timing out all commands and going ahead and > attaching anyhow? If this is the case I think we'd get a good result > if we just fixed that and had the driver simply not attach. Then your > resume will not be broken. > > > > I'd be more comfortable with some kind of ACPI black list or patch or > > > something? What is normal for handling broken ACPI? > > > > I would be more comfortable with this general approach as well. However, > > I've had to submit several patches for individual Chromebooks related to > > backlight control since the VBT also is misconfigured. Would it be > > possible to find a blacklist mechanism that didn't require identifying > > each Chromebook separately, since they seem to have this issue on an > > ongoing basis? > > So, if you are booting the Chromebook in some weird way, is this a > problem that can be addressed by patching SeaBIOS instead of the > kernel? The internet says the SeaBIOS payload is replaceable on the > Chromebook. > > Can it fix the ACPI tables to be correct before lauching Linux? > > > A more general approach might be to verify the ACPI interrupt for > > systems matching the first three identifiers. > > Testing the interrupt and failing driver attach if it doesn't work > seems very reasonable to me, I would view that as a bug fix in the driver. > > Jason -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
