Bug 95931

Summary:	Linx 7 Tablet PC - Only boots on kernel 3.14
Product:	ACPI	Reporter:	beta990 (francois5537)
Component:	BIOS	Assignee:	acpi_bios
Status:	CLOSED WILL_NOT_FIX
Severity:	blocking	CC:	aaron.lu, francois5537
Priority:	P1
Hardware:	x86-64
OS:	Linux
Kernel Version:	4.0	Subsystem:
Regression:	No	Bisected commit-id:
Attachments:	dmesg output, DSDT

Description beta990 2015-04-01 11:18:19 UTC

Created attachment 172931 [details]
dmesg output, DSDT

Tried to run Arch Linux on Linx 7 (http://www.linx-tablets.com/linx-7.html), works/boots on 3.14.37-1-lts kernel.

When I upgrade to kernel 3.15> <=3.19, I can only boot with acpi=off as kernel parameter.

Unfortunately it hangs/freezes at initial ramdisk (on upgraded kernel), and I'm unable to provide any (display) output.
So I have provided output/debug info from the 3.14 kernel.

Many Thanks!

PS. Reason for upgrade: touchscreen support (Goodix), drivers, fixes for btrfs, etc.

Comment 1 Aaron Lu 2015-04-10 07:51:36 UTC

Do I understand correctly that with acpi=off, you can boot till initial ramdisk, then hang; without acpi=off, system doesn't boot?

Comment 2 beta990 2015-04-10 08:46:41 UTC

Hello Aaron,

Forget to update the report, booting works fine with: noefi reboot=pci,force irqpoll

noefi: doesn't boot without it
reboot=pci,force: required for rebooting
irqpoll: fix irq warnings

Also tried to boot with other acpi flags, but had no effect (freeze at initial ramdisk).

Broken BIOS?

Thanks for looking at this issue. :)

Comment 3 Aaron Lu 2015-04-10 09:04:46 UTC

(In reply to beta990 from comment #2)
> Hello Aaron,
> 
> Forget to update the report, booting works fine with: noefi reboot=pci,force
> irqpoll
> 
> noefi: doesn't boot without it

In comment #1, you have mentioned acpi=off. Is it no longer necessary with noefi?

> reboot=pci,force: required for rebooting

Seems to be common for Baytrail-T platforms, ASUS T100 is also the same.

> irqpoll: fix irq warnings

Not sure about this.

Comment 4 beta990 2015-04-10 09:12:37 UTC

(In reply to Aaron Lu from comment #3)
> (In reply to beta990 from comment #2)
> > Hello Aaron,
> > 
> > Forget to update the report, booting works fine with: noefi
> reboot=pci,force
> > irqpoll
> > 
> > noefi: doesn't boot without it
> 
> In comment #1, you have mentioned acpi=off. Is it no longer necessary with
> noefi?
> 
> > reboot=pci,force: required for rebooting
> 
> Seems to be common for Baytrail-T platforms, ASUS T100 is also the same.
> 
> > irqpoll: fix irq warnings
> 
> Not sure about this.

> In comment #1, you have mentioned acpi=off. Is it no longer necessary with
> noefi?
Correct, this are the flags I use to boot successfully: noefi reboot=pci,force irqpoll 

However when using acpi=off instead of noefi, it boots but it cannot find the HDD/eMMC.

> > reboot=pci,force: required for rebooting
> 
> Seems to be common for Baytrail-T platforms, ASUS T100 is also the same.
Thanks, indeed found this flag on an ASUS T100 topic.

If you need any more info, please let me know. :)

Comment 5 Aaron Lu 2015-04-14 06:57:40 UTC

(In reply to beta990 from comment #4)
> (In reply to Aaron Lu from comment #3)
> > (In reply to beta990 from comment #2)
> > > Hello Aaron,
> > > 
> > > Forget to update the report, booting works fine with: noefi
> reboot=pci,force
> > > irqpoll
> > > 
> > > noefi: doesn't boot without it
> > 
> > In comment #1, you have mentioned acpi=off. Is it no longer necessary with
> > noefi?
> > 
> > > reboot=pci,force: required for rebooting
> > 
> > Seems to be common for Baytrail-T platforms, ASUS T100 is also the same.
> > 
> > > irqpoll: fix irq warnings
> > 
> > Not sure about this.
> 
> > In comment #1, you have mentioned acpi=off. Is it no longer necessary with
> > noefi?
> Correct, this are the flags I use to boot successfully: noefi
> reboot=pci,force irqpoll 

From the kernel-parameters document, the noefi is used to disable EFI runtime service, I'm not familiar what EFI runtime service Linux currently makes use of, need to check this.

> 
> However when using acpi=off instead of noefi, it boots but it cannot find
> the HDD/eMMC.

I suppose that is because the eMMC controller is listed in the ACPI table(instead of as a PCI device) and if ACPI is disabled, it can't be enumerated/probed.

So with the above kernel cmdline, I suppose everything works well?

Comment 6 beta990 2015-04-14 08:54:55 UTC

Hi Aaron,

Yep, it now works fine now. :)

When I opened the request, I hadn't found/tested the noefi flag.
Seems this fixes a lot of issues on the board/BIOS.
reboot=pci,force irqpoll flags are still needed, can't only concluded the board isn't 100% compatible with Linux.
But the workarounds work fine. ;)

Will close the report, since it seems more boards have these (EFI) problems.

Thanks for the support.