drm/nouveau: bail out of auxch transaction if we repeatedly recieve defers
There's one known case where we never stop recieving DEFER, and loop here
forever. Lets not do that..
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nouveau_dp.c b/drivers/gpu/drm/nouveau/nouveau_dp.c
index f954ad9..deeb21c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dp.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dp.c
@@ -483,7 +483,7 @@
ctrl |= (cmd << NV50_AUXCH_CTRL_CMD_SHIFT);
ctrl |= ((data_nr - 1) << NV50_AUXCH_CTRL_LEN_SHIFT);
- for (;;) {
+ for (i = 0; i < 16; i++) {
nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl | 0x80000000);
nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl);
nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl | 0x00010000);
@@ -502,6 +502,12 @@
break;
}
+ if (i == 16) {
+ NV_ERROR(dev, "auxch DEFER too many times, bailing\n");
+ ret = -EREMOTEIO;
+ goto out;
+ }
+
if (cmd & 1) {
if ((stat & NV50_AUXCH_STAT_COUNT) != data_nr) {
ret = -EREMOTEIO;