VBIOS can't switch to external device when I use xf86-video-ati driver

[Jhih-Sin Chen]

On 6/25/08, Alex Deucher <alexdeucher at gmail.com> wrote:
> On Wed, Jun 25, 2008 at 10:50 AM, Jhih-Sin Chen <jschen.cse at gmail.com> wrote:
> > On Wed, Jun 25, 2008 at 10:26 PM, Alex Deucher <alexdeucher at gmail.com> wrote:
> >> On Wed, Jun 25, 2008 at 9:56 AM, Jhih-Sin Chen <jschen.cse at gmail.com> wrote:
> >>> Hi,
> >>>
> >>> I am using Radeon HD 3470 card with xf86-video-ati 6.8.192 on my laptop.
> >>> I try to implement hotkey function to switch display device.
> >>> I have set _DOS parameter in ACPI and ask VBIOS to switch display
> >>> device but it fails.
> >>>
> >>> However, the hotkey function can switch display device successfully
> >>> when I use "vesa" driver.
> >>> Do you have any suggetion on this issue? Thanks.
> >>
> >> It's disabled on purpose.  The bios goes behind the driver's back and
> >> messes with the hardware which can lead to bad state or possibly hw
> >> locks.  You can control the outputs with xrandr so please use that.
> >> On most laptops you can even change the video hotkey to produce acpi
> >> events rather than banging the hw directly and then you tie that event
> >> to a script that runs xrandr commands.
> >>
> >> Alex
> >>
> >
> > Hi,
> >
> > But I can't use xrandr to swtich display device to HDMI. Is it a
> > limitation of xrandr or anything wrong?
> >
>
> what sort of problem are you having?
> xrandr --output HDMI-0 --auto
> should do the trick.
>
> What does the output of xrandr look like?

"xrandr -q" always show "hdmi-0 disconnected" even if my laptop
connect to HDMI device.
"xrandr --output HDMI-0 --auto" show nothing and can't switch to HDMI.

Where is the start point to debug this issue? Thank you.


>
> > So I wanna use VBIOS to switch display device. Could you kindly tell
> > me how to enabled VBIOS switch function on xf86-video-ati or give a
> > start point for me to study? Thanks.
> >
>
> The driver doesn't use it.  It just disables the use of it.
>
> Alex
>