drm/i915: Use ktime on wait_for
We use jiffies to determine when wait expires. However Imre did find out that jiffies can and will do a >1 increments on certain situations [1]. When this happens in a wait_for loop, we return timeout errorneously much earlier than what the real wallclock would say. We can't afford our waits to timeout prematurely. Discard jiffies and change to ktime to detect timeouts. v2: added bugzilla entry (Imre), added stable (Chris) Reported-by: Imre Deak <imre.deak@intel.com> References: https://lkml.org/lkml/2018/4/18/798 [1] Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105771 Cc: Imre Deak <imre.deak@intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20180423113754.28424-1-mika.kuoppala@linux.intel.com
This commit is contained in:
Родитель
672e314b21
Коммит
3085982c6b
|
@ -49,12 +49,12 @@
|
|||
* check the condition before the timeout.
|
||||
*/
|
||||
#define __wait_for(OP, COND, US, Wmin, Wmax) ({ \
|
||||
unsigned long timeout__ = jiffies + usecs_to_jiffies(US) + 1; \
|
||||
const ktime_t end__ = ktime_add_ns(ktime_get_raw(), 1000ll * (US)); \
|
||||
long wait__ = (Wmin); /* recommended min for usleep is 10 us */ \
|
||||
int ret__; \
|
||||
might_sleep(); \
|
||||
for (;;) { \
|
||||
bool expired__ = time_after(jiffies, timeout__); \
|
||||
const bool expired__ = ktime_after(ktime_get_raw(), end__); \
|
||||
OP; \
|
||||
if (COND) { \
|
||||
ret__ = 0; \
|
||||
|
|
Загрузка…
Ссылка в новой задаче