On 8/27/19 5:45 PM, Fernando Pacheco wrote:
During normal driver unload we attempt to disable GuC communication
while it is currently stopped. This results in a nop'd call to
intel_guc_ct_disable within guc_disable_communication because
stop/disable rely on the same flag to prevent further comms with CT.
We can avoid the call to disable and still leave communication in a
satisfactory state by extracting a set of shared steps from stop/disable.
This set can include guc_disable_interrupts as we do not require the
single caller of guc_stop_communication to be atomic:
"drm/i915/selftests: Fixup atomic reset checking".
This situation (stop -> disable) only occurs during intel_uc_fini_hw,
so during fini, call guc_disable_communication only if currently enabled.
The symmetric calls to enable/disable remain unmodified for all other
scenarios.
Signed-off-by: Fernando Pacheco <fernando.pacheco@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/uc/intel_uc.c | 30 ++++++++++++++++-----------
1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
index 71ee7ab035cc..29a9eec60d2e 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
@@ -224,17 +224,7 @@ static int guc_enable_communication(struct intel_guc *guc)
return 0;
}
-static void guc_stop_communication(struct intel_guc *guc)
-{
- intel_guc_ct_stop(&guc->ct);
-
- guc->send = intel_guc_send_nop;
- guc->handler = intel_guc_to_host_event_handler_nop;
-
- guc_clear_mmio_msg(guc);
-}
-
-static void guc_disable_communication(struct intel_guc *guc)
+static void __guc_stop_communication(struct intel_guc *guc)
{
/*
* Events generated during or after CT disable are logged by guc in
@@ -247,6 +237,20 @@ static void guc_disable_communication(struct intel_guc *guc)
guc->send = intel_guc_send_nop;
guc->handler = intel_guc_to_host_event_handler_nop;
+}
+
+static void guc_stop_communication(struct intel_guc *guc)
+{
+ intel_guc_ct_stop(&guc->ct);
+
The only difference between intel_guc_ct_stop() and
intel_guc_ct_disable() is that in the latter we also tell guc that we've
disabled the buffers. We could probably just add a check to return early
if !intel_guc_is_running() in intel_guc_ct_disable() and drop the
stop/disable differentiation entirely, but that doesn't need to happen
in this patch.
+ __guc_stop_communication(guc);
+
+ DRM_INFO("GuC communication stopped\n");
+}
+
+static void guc_disable_communication(struct intel_guc *guc)
+{
Are we now guaranteed that guc_disable_communication() is called only of
communication is actually enabled? if so, we could add here a:
GEM_BUG_ON(!guc_communication_enabled(guc));
with or without that:
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
Daniele
+ __guc_stop_communication(guc);
intel_guc_ct_disable(&guc->ct);
@@ -537,7 +541,9 @@ void intel_uc_fini_hw(struct intel_uc *uc)
if (intel_uc_supports_guc_submission(uc))
intel_guc_submission_disable(guc);
- guc_disable_communication(guc);
+ if (guc_communication_enabled(guc))
+ guc_disable_communication(guc);
+
__uc_sanitize(uc);
}
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