Allow/Fix use of multiple ZaphodHead outputs per x-screen. (v2)

Defining multiple ZaphodHead outputs per x-screen in a
multiple x-screen's per gpu configuration caused all
outputs except one per x-screen to go dark, because
there was a fixed mapping x-screen number -> crtc number,
limiting the number of crtc's per x-screen to one.

On a ZaphodHead's setup, be more clever and assign
as many crtc's to a given x-screen as there are
ZaphodHeads defined for that screen, assuming
there are enough unused crtc's available.

Tested on a triple display setup with different combos
of one, two or three ZaphodHeads per one, two or three
x-screens.

This is a port of similar code from xf86-video-nouveau.

v2: Implement suggestions by Michel Dänzer: Less verbose
    debug output, more clear warning message on crtc allocation
    failure. Move clearing of per gpu assigned_crtc mask to
    CloseScreen, indeed testing shows no need for the more
    complex new server generation check from v1.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
(v1) Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/radeon_kms.c b/src/radeon_kms.c
index 0690ef06..25a746db 100644
--- a/src/radeon_kms.c
+++ b/src/radeon_kms.c
@@ -1457,10 +1457,14 @@ static Bool RADEONCloseScreen_KMS(CLOSE_SCREEN_ARGS_DECL)
 {
     ScrnInfoPtr pScrn = xf86ScreenToScrn(pScreen);
     RADEONInfoPtr  info  = RADEONPTR(pScrn);
+    RADEONEntPtr pRADEONEnt = RADEONEntPriv(pScrn);
 
     xf86DrvMsgVerb(pScrn->scrnIndex, X_INFO, RADEON_LOGLEVEL_DEBUG,
 		   "RADEONCloseScreen\n");
 
+    /* Clear mask of assigned crtc's in this generation */
+    pRADEONEnt->assigned_crtcs = 0;
+
     drmmode_uevent_fini(pScrn, &info->drmmode);
     radeon_drm_queue_close(pScrn);
     radeon_cs_flush_indirect(pScrn);