Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
> As we require a context switch to ensure that the current context is
> switched out and saved to memory, perform an explicit switch to the
> kernel context and wait for it.
The patch subject is not incorrect. Just feels that the kernel
context is a patsy in here.
So I would s/kernel// on subject but keep in commit msg
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/selftest_lrc.c | 37 +++++++++++++++++++-------
> 1 file changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
> index d7f98aada626..95da6b880e3f 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
> @@ -4015,6 +4015,31 @@ static int emit_semaphore_signal(struct intel_context *ce, void *slot)
> return 0;
> }
>
> +static int context_sync(struct intel_context *ce)
> +{
> + struct i915_request *rq;
> + struct dma_fence *fence;
> + int err = 0;
> +
> + rq = intel_engine_create_kernel_request(ce->engine);
> + if (IS_ERR(rq))
> + return PTR_ERR(rq);
> +
> + fence = i915_active_fence_get(&ce->timeline->last_request);
> + if (fence) {
> + i915_request_await_dma_fence(rq, fence);
> + dma_fence_put(fence);
> + }
> +
> + rq = i915_request_get(rq);
> + i915_request_add(rq);
> + if (i915_request_wait(rq, 0, HZ / 2) < 0)
> + err = -ETIME;
> + i915_request_put(rq);
> +
> + return err;
> +}
> +
> static int live_lrc_layout(void *arg)
> {
> struct intel_gt *gt = arg;
> @@ -4638,16 +4663,10 @@ static int __lrc_timestamp(const struct lrc_timestamp *arg, bool preempt)
> wmb();
> }
>
> - if (i915_request_wait(rq, 0, HZ / 2) < 0) {
> - err = -ETIME;
> - goto err;
> - }
> -
> - /* and wait for switch to kernel */
> - if (igt_flush_test(arg->engine->i915)) {
> - err = -EIO;
> + /* and wait for switch to kernel (to save our context to memory) */
> + err = context_sync(arg->ce[0]);
> + if (err)
> goto err;
> - }
>
> rmb();
For me the context_sync could be context_flush and it would
allow the rmb() to be snuck inside.
But I seem to gravitate towards lower resolution and
apparently you prefer to be more fine grained and
explicit on callsites so,
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
>
> --
> 2.25.1
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