Rotating tablet screen updates lid state but doesn't generate an event

Rotating tablet screen updates lid state but doesn't generate an event

[Toby Cubitt]

Hi,

I hope this is the right list to post this kind of question.

I'm running a 2.6.23 kernel (with the tuxonice and Gentoo patchsets
applied) on a Toshiba Portege M400 tablet PC, and I have the legacy
/proc/acpi support built into the kernel (CONFIG_ACPI_PROCFS=y and
CONFIG_ACPI_PROC_EVENT=y), since acpid still depends on it for now. I
also have Toshiba ACPI support built into the kernel, in case that's
also relevant (CONFIG_ACPI_TOSHIBA=y).

When I open or close the lid as on a normal laptop,
/proc/acpi/button/lid/LID/state is updated and acpi
"button/lid" events are generated in /proc/acpi/event, as expected.
However, when I rotate the screen into tablet mode, although the lid
state is updated to "closed", nothing is generated in /proc/acpi/event.
Then, when I lift the lid to rotate it back to normal laptop position, a
"button/lid" event _is_ generated in /proc/acpi/event, identical to
normal lid events (and the lid state is updated to "open").

So it seems as though acpi is correctly identifying closing the lid and
rotating the screen into tablet mode as two different types of events,
but isn't writing anything to /proc/acpi/event for the latter. On the
other hand, it is generating identical events for both opening the lid
and rotating the screen back to laptop mode.

I guess the correct behaviour would be along the lines of what
apparently happens in Thinkpad tablets: opening and closing the lid
should generate "button/lid" events, and rotating the screen to and from
tablet mode should generate a different type of event. (Though if
the kernel just generated any event other than "button/lid" when the
screen was rotated to tablet mode, it would still be usable.)

I'm happy to provide more information if it would be helpful, but I have
no experience at all in helping debug kernel code, so I'm not sure what
I should be telling you.

Thanks for any help,

Toby

Re: Rotating tablet screen updates lid state but doesn't generate an event

[Thomas Ibbotson]

Toby Cubitt <tsc25 <at> cantab.net> writes:

>
> Hi,
>
> I hope this is the right list to post this kind of question.
>
> I'm running a 2.6.23 kernel (with the tuxonice and Gentoo patchsets
> applied) on a Toshiba Portege M400 tablet PC, and I have the legacy
> /proc/acpi support built into the kernel (CONFIG_ACPI_PROCFS=y and
> CONFIG_ACPI_PROC_EVENT=y), since acpid still depends on it for now. I
> also have Toshiba ACPI support built into the kernel, in case that's
> also relevant (CONFIG_ACPI_TOSHIBA=y).
>
> When I open or close the lid as on a normal laptop,
> /proc/acpi/button/lid/LID/state is updated and acpi
> "button/lid" events are generated in /proc/acpi/event, as expected.
> However, when I rotate the screen into tablet mode, although the lid
> state is updated to "closed", nothing is generated in /proc/acpi/event.
> Then, when I lift the lid to rotate it back to normal laptop position, a
> "button/lid" event _is_ generated in /proc/acpi/event, identical to
> normal lid events (and the lid state is updated to "open").
>
> So it seems as though acpi is correctly identifying closing the lid and
> rotating the screen into tablet mode as two different types of events,
> but isn't writing anything to /proc/acpi/event for the latter. On the
> other hand, it is generating identical events for both opening the lid
> and rotating the screen back to laptop mode.
>
> I guess the correct behaviour would be along the lines of what
> apparently happens in Thinkpad tablets: opening and closing the lid
> should generate "button/lid" events, and rotating the screen to and from
> tablet mode should generate a different type of event. (Though if
> the kernel just generated any event other than "button/lid" when the
> screen was rotated to tablet mode, it would still be usable.)
>
> I'm happy to provide more information if it would be helpful, but I have
> no experience at all in helping debug kernel code, so I'm not sure what
> I should be telling you.
>
> Thanks for any help,
>
> Toby

Hi,

I am having exactly the same problem with a Toshiba Portege R400. Can anyone
point me in the right direction for tackling this issue?

Thanks,
Tom

Re: Rotating tablet screen updates lid state but doesn't generate an event

[Matthew Garrett]

On Mon, Jan 14, 2008 at 01:39:23PM +0000, Toby Cubitt wrote:

> So it seems as though acpi is correctly identifying closing the lid and
> rotating the screen into tablet mode as two different types of events,
> but isn't writing anything to /proc/acpi/event for the latter. On the
> other hand, it is generating identical events for both opening the lid
> and rotating the screen back to laptop mode.

It's likely that your firmware sends some other sort of event for this. 
There's nothing in the ACPI spec for handing tablet state changes, so it 
tends to vary by vendor.

> I'm happy to provide more information if it would be helpful, but I have
> no experience at all in helping debug kernel code, so I'm not sure what
> I should be telling you.

Can you send a copy of the output of the acpidump command?

-- 
Matthew Garrett | mjg59@srcf.ucam.org