From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: References: <20200213192606.63025-1-dale.b.stimson@intel.com> From: Antonio Argenziano Message-ID: <9d522af3-470d-52f2-51e1-fef2ffdcfaa8@intel.com> Date: Fri, 14 Feb 2020 10:43:01 -0800 MIME-Version: 1.0 In-Reply-To: <20200213192606.63025-1-dale.b.stimson@intel.com> Content-Language: en-US Subject: Re: [igt-dev] [PATCH i-g-t] lib/i915/gem_engine_topology.c - intel_get_current_engine invalid result List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: igt-dev-bounces@lists.freedesktop.org Sender: "igt-dev" To: Dale B Stimson , igt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Cc: Petri Latvala List-ID: On 13/02/20 11:26, Dale B Stimson wrote: > Function intel_get_current_engine() should return NULL (instead of > engine 0) if there are no engines. > > Function intel_init_engine_list() should not store potential engine > data in the output structure unless the engine is present. > > Function intel_init_engine_list() should arguably not filter the static > engine list with gem_has_ring if fd == -1, so that subtests can still > be individually invoked to show subtest FAIL instead of test notrun. > > Symptom: A device open failure in gem_ctx_isolation resulted in > an endless __for_each_physical_engine "per-engine" loop with the > purported last potential engine being processed every time. > > Diagnosis: device open (or debugfs open) failed, leaving fd == -1. > Control skipped the rest of the initial igt_fixture block, after > which an attempt was made to iterate through engines using macro > __for_each_physical_engine. > > Macro __for_each_physical_engine called intel_init_engine_list() > to initialize the loop control data. Because fd == -1, > intel_init_engine_list() fell back to using __for_each_static_engine(). > All of the engines in the static engine list are rejected due to > gem_has_ring returning false (because of fd == -1), leaving 0 engines. > That resulted in loop control data with engine_data.nengines == 0 > and the data for the last engine considered stored at index 0. > > Still in macro __for_each_physical_engine, intel_get_current_engine() > was called to get the engine to process. It should have returned NULL, > but instead returned the engine entry at index 0, which > had received information describing the last potential engine. > This happened without end. > > Signed-off-by: Dale B Stimson > --- > lib/i915/gem_engine_topology.c | 29 ++++++++++++++++------------- > 1 file changed, 16 insertions(+), 13 deletions(-) > > diff --git a/lib/i915/gem_engine_topology.c b/lib/i915/gem_engine_topology.c > index 9daa03df4..b8ed49bc9 100644 > --- a/lib/i915/gem_engine_topology.c > +++ b/lib/i915/gem_engine_topology.c > @@ -156,10 +156,10 @@ static void query_engine_list(int fd, struct intel_engine_data *ed) > struct intel_execution_engine2 * > intel_get_current_engine(struct intel_engine_data *ed) > { > - if (!ed->n) > - ed->current_engine = &ed->engines[0]; > - else if (ed->n >= ed->nengines) > + if (ed->n >= ed->nengines) > ed->current_engine = NULL; > + else if (!ed->n) > + ed->current_engine = &ed->engines[0]; > > return ed->current_engine; > } > @@ -222,18 +222,21 @@ struct intel_engine_data intel_init_engine_list(int fd, uint32_t ctx_id) > igt_debug("using pre-allocated engine list\n"); > > __for_each_static_engine(e2) { > - struct intel_execution_engine2 *__e2 = > - &engine_data.engines[engine_data.nengines]; > - > - strcpy(__e2->name, e2->name); > - __e2->instance = e2->instance; > - __e2->class = e2->class; > - __e2->flags = e2->flags; > - __e2->is_virtual = false; > - > if (igt_only_list_subtests() || > - gem_has_ring(fd, e2->flags)) > + (fd < 0) || Patch LGTM, Chris do you have any issues merging this before someone implements some tests for the infrastructure? Acked-by: Antonio Argenziano > + gem_has_ring(fd, e2->flags)) { > + struct intel_execution_engine2 *__e2 = > + &engine_data.engines[ > + engine_data.nengines]; > + > + strcpy(__e2->name, e2->name); > + __e2->instance = e2->instance; > + __e2->class = e2->class; > + __e2->flags = e2->flags; > + __e2->is_virtual = false; > + > engine_data.nengines++; > + } > } > return engine_data; > } > _______________________________________________ igt-dev mailing list igt-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/igt-dev