Check for overflow in udelay/usleep_range use in __xe_mmio_wait32
and pick the correct helper accordingly. Fix sign-overflow and avoid
growing delays becoming intollerably large by capping the in-loop
wait time. Simplify sleep_min assignment by removing redundant cast.
Fixes: 5c09bd6ccd41 ("drm/xe/mmio: Move xe_mmio_wait32() to xe_mmio.c")
Signed-off-by: Alan Previn <[email protected]>
Assisted-by: Github-Copilot:Claude-Sonnet-4-6
---
drivers/gpu/drm/xe/xe_mmio.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
index 7fa18dfcb5a2..cf2e05aaa4b2 100644
--- a/drivers/gpu/drm/xe/xe_mmio.c
+++ b/drivers/gpu/drm/xe/xe_mmio.c
@@ -349,11 +349,23 @@ static int __xe_mmio_wait32(struct xe_mmio *mmio, struct
xe_reg reg, u32 mask, u
if (ktime_after(ktime_add_us(cur, wait), end))
wait = ktime_us_delta(end, cur);
- if (atomic)
- udelay(wait);
- else
- usleep_range(wait, wait << 1);
- wait <<= 1;
+#define __XE_MMIO_WAIT_MAX_INLOOP_TIME (100 * USEC_PER_MSEC)
+ if (atomic) {
+ if (wait <= MAX_UDELAY_MS * USEC_PER_MSEC)
+ udelay(wait);
+ else
+ mdelay(DIV_ROUND_UP(wait, USEC_PER_MSEC));
+ } else {
+ usleep_range(wait, __XE_MMIO_WAIT_MAX_INLOOP_TIME);
+ }
+ /*
+ * As we keep doubling the wait time for every check that
fails, cap the
+ * in-loop delay-or-sleep to less than 2x 100 miliseconds to
prevent from
+ * expanding 'wait' into exponentially longer wait times per
loop that
+ * end up delaying the next completion check way later than
tolerable.
+ */
+ wait = wait < __XE_MMIO_WAIT_MAX_INLOOP_TIME >> 1 ?
+ wait << 1 : __XE_MMIO_WAIT_MAX_INLOOP_TIME;
}
if (ret != 0) {
base-commit: 71bc3b7cc55631a9b3807da98e2b2880838b9623
--
2.43.0
