Re: DRM modesetting & sysfs

["Jakob Bornecrantz" <wallbraker@gmail.com>]

On Tue, Apr 8, 2008 at 10:17 PM, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
>
>  I just pushed a few changes updating the DRM modesetting sysfs support, both
>  for debugging and eventual HAL friendliness.
>
>  So far, the support is limited to describing outputs and generating hotplug
>  events.  A typical "card0" directory now looks like this:
>
>  .
>  |-- card0-DAC-1
>  |   |-- device -> ../../../../../../devices/pci0000:00/0000:00:02.0/drm/card0
>  |   |-- dpms
>  |   |-- edid
>  |   |-- modes
>  |   |-- power
>  |   |   `-- wakeup
>  |   |-- status
>  |   |-- subsystem -> ../../../../../../class/drm
>  |   `-- uevent
>  |-- card0-LVDS-1
>  |   |-- device -> ../../../../../../devices/pci0000:00/0000:00:02.0/drm/card0
>  |   |-- dpms
>  |   |-- edid
>  |   |-- modes
>  |   |-- power
>  |   |   `-- wakeup
>  |   |-- status
>  |   |-- subsystem -> ../../../../../../class/drm
>  |   `-- uevent
>  |-- dev
>  |-- device -> ../../../../../devices/pci0000:00/0000:00:02.0
>  |-- dri_library_name
>  |-- power
>  |   `-- wakeup
>  |-- subsystem -> ../../../../../class/drm
>  `-- uevent
>
>  Each output is listed, prefixed with its associated card number to
>  disambiguate it at the top level /sys/class/drm directory (where it also has
>  some symlinks).  Currently, only DPMS, EDID, mode list and connection status
>  properties are exported, but we could list more as needed.  You can
>  use 'udevmonitor --env' to look for hotplug events; you should see several at
>  load time, and presumably some at connection hotplug time (though I haven't
>  gotten that working yet, any ideas Jakob?).
>

I was going to suggest that you plug it into the hotplug_stage_two
function but it looks like you have already done that. Things might be
routed differently now then since the last time I looked at the code,
are you sure that stage_two is being run?

>  Any thoughts on the interface?  Anything in particular people would like to
>  see?
>

Looks good, can you write to dpms, that is turn a monitor on and of,
that would be slightly cool but not overly useful. On the whole I
think exporting properties are fine, but I don't think setting modes
and crtc's are to be done in sysfs. However it is entirely possible.

>  Thanks,
>  Jesse

Cheers Jakob.