sna: Ensure errno is set after failure before reporting a modeset failure

A few paths we report a sanity check failure which do not set errno, but
we then print out the errno as part of our message to the user. Set it
to a sane value in those cases.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/src/sna/sna_display.c b/src/sna/sna_display.c
index fbd7cff..af884c4 100644 (file)
--- a/src/sna/sna_display.c
+++ b/src/sna/sna_display.c
@@ -869,8 +869,10 @@ rotation_set(struct sna *sna, struct plane *p, uint32_t desired)
        if (desired == p->rotation.current)
                return true;
 
-       if ((desired & p->rotation.supported) == 0)
+       if ((desired & p->rotation.supported) == 0) {
+               errno = EINVAL;
                return false;
+       }
 
        DBG(("%s: obj=%d, type=%x prop=%d set-rotation=%x\n",
             __FUNCTION__, p->id, LOCAL_MODE_OBJECT_PLANE, p->rotation.prop, desired));
@@ -961,8 +963,10 @@ sna_crtc_apply(xf86CrtcPtr crtc)
                       xf86IsEntityShared(crtc->scrn->entityList[0]));
 
                output_ids[output_count] = to_connector_id(output);
-               if (++output_count == ARRAY_SIZE(output_ids))
+               if (++output_count == ARRAY_SIZE(output_ids)) {
+                       errno = EINVAL;
                        return false;
+               }
        }
 
        VG_CLEAR(arg);
@@ -2055,6 +2059,8 @@ retry: /* Attach per-crtc pixmap or direct */
        sna_crtc->bo = bo;
        mode_to_kmode(&sna_crtc->kmode, mode);
        if (!sna_crtc_apply(crtc)) {
+               int err = errno;
+
                kgem_bo_destroy(&sna->kgem, bo);
 
                if (!sna_crtc->shadow) {
@@ -2063,7 +2069,7 @@ retry: /* Attach per-crtc pixmap or direct */
                }
 
                xf86DrvMsg(crtc->scrn->scrnIndex, X_ERROR,
-                          "failed to set mode: %s\n", strerror(errno));
+                          "failed to set mode: %s [%d]\n", strerror(err), err);
 
                sna_crtc->offset = saved_offset;
                sna_crtc->transform = saved_transform;