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

[Alex Deucher]

On Thu, Jun 26, 2008 at 2:58 AM, Jhih-Sin Chen <jschen.cse at gmail.com> wrote:
> 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.
>

We'd need to see your log.  Can you post your xorg log and config?

In the meantime you can force the output on with xrandr using something like:

xrandr --newmode "1024x768R"   56.00  1024 1072 1104 1184  768 771 775
790 +hsync -vsync
xrandr --addmode HDMI-0 "1024x768R"
xrandr --output HDMI-0 --mode "1024x768R"

Replace the 1024x768 mode with whatever mode you want to use on your HDMI port.
you can generate the modeline with cvt:
cvt -r 1024 768 60
or (non-reduced blanking modes):
cvt 1024 768 60

Thanks,

Alex