RandR (etc) DriverFunc

[Thomas Winischhofer]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Egbert Eich wrote:
| Thomas Winischhofer writes:
|  > -----BEGIN PGP SIGNED MESSAGE-----
|  > Hash: SHA1
|  >
|  > Egbert Eich wrote:
|  > | Andy Ritger writes:
|  > |  >
|  > |  > Sorry I didn't get a chance to respond to this yesterday, Thomas
|  > |  > and Egbert.
|  > |  >
|  > |  > This is a good point, Thomas.
|  > |  >
|  > |  > In the SetConfig case, it's nice for the driver to be notified
|  > |  > when the size is changed, even if the rotation is not changing
(eg,
|  > |  > to reallocate vidmem for the root window's new resolution), though
|  > |  > I'd say it's not crucial (atleast for the NVIDIA driver).
|  > |
|  > | Hm, when we change the size we call setMode() in the driver
|  > | anyway. Doesn't this suffice?
|  > | Currently we don't reallocate vidmem as we don't ever change the
|  > | size of the video memory. This is not really supported in our
|  > | model. This shortcoming needs to be resolved when reworking the
|  > | driver.
|  >
|  >
|  > While we are at it (size, namely):
|  >
|  > I would love a driver-callback to set the "initial" randr size after
|  > screeninit().
|  >
|  > Currently, RandR is initialized after the driver's ScreenInit(). So the
|  > driver MUST return the real virtual sizes when exiting from
ScreenInit()
|  > in order to make the server allocate the (correct) maximum root
window size.
|  >
|  > So the server always starts with size #0 (as seen through
|  > xrandr-semantics). However, there is no way to start the server with
|  > size #1.
|  >
|  > What would that be good for?
|  >
|  > Simple: I would like to be able to start the server in MergedFB
|  > (TwinView) mode, but with only one head attached and a clone-mode
as the
|  > startup mode, and then let the user attach (or switch on) the second
|  > head, switch to a non-clone mode and thereby - essentially - switch
from
|  > single-head to dual-head operation.
|  >
|  > Currently this is impossible because there is no way to issue a
|  > RandR-resize from within the driver after ScreenInit() but before
|  > quitting InitOutput(). The RandR part would be server-side only (hence
|  > pretty simple) because the server is in the setup-phase where no
clients
|  > need to be notified.
|  >
|  > Hence, I need
|  >
|  > 1) a call-back which is called AFTER xf86RandRInit() in Initoutput() in
|  > order to issue a resize (to the startup mode-size) at this point,
|  >
|  > 2) a RandR-symbol accessible from the driver to actually issue a
resize.
|  >
|  > Comments?
|  >
|
| This gets ugly. You are suggesting to change the root window size
| (ie double it) and share this root window between two different
| displays (which have a different viewport).
| I don't know if this works well. As I read randr it is tightly coupled
| to the mode setting on a head. That means root_window_size == mode_size.


In MergedFB, root_window_size = metamode_size.


| One needs to see how this semantics can be extended. Let me think about
| how this can be done - without adding another wart to an extension
| which is already not doing exactly what we want.

No, you misunderstood me.

To make it simpler, forget MergedFB mode. Think single head:

1) User starts X with virtual screen 1280x1024, and modes 1280x1024,
1024x768.

2) User executes xrandr -s 1 and thereby switches to 1024x768.

What I want is a way to do that second step during server start, ie not
always start with size #0, but - for example - size #1. The root window
size is always the same, 1280x1024. Just issue a RandR-resize from
within the driver before clients can connect.

The example in my previous mail was one practical application of this
facility. RandR works execellently with MergedFB already (INCLUDING
xinerama and with non-rectangular layouts).

Thomas

- --
Thomas Winischhofer
Vienna/Austria
thomas AT winischhofer DOT net          http://www.winischhofer.net/
twini AT xfree86 DOT org
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.0 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org

iD8DBQFCOeLrzydIRAktyUcRAv6ZAKCLiW2HvShd3xbqVp1fme59loIhhgCgtY2L
tuOrnaVvo4WbpQzPxCjShPw=
=VLCn
-----END PGP SIGNATURE-----