drm/i915/pmu: Support multiple GPUs

With discrete graphics system can have both integrated and discrete GPU
handled by i915.

Currently we use a fixed name ("i915") when registering as the uncore PMU
provider which stops working in this case.

To fix this we add the PCI device name string to non-integrated devices
handled by us. Integrated devices keep the legacy name preserving
backward compatibility.

v2:
 * Detect IGP and keep legacy name. (Michal)
 * Use PCI device name as suffix. (Michal, Chris)

v3:
 * Constify the name. (Chris)
 * Use pci_domain_nr. (Chris)

v4:
 * Fix kfree_const usage. (Chris)

v5:
 * kfree_const does not work for modules. (Chris)
 * Changed is_igp helper to take i915.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191016093802.12483-1-tvrtko.ursulin@linux.intel.com

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index d050871..00fe401 100644 (file)
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -1080,6 +1080,17 @@ static void i915_pmu_unregister_cpuhp_state(struct i915_pmu *pmu)
        cpuhp_remove_multi_state(cpuhp_slot);
 }
 
+static bool is_igp(struct drm_i915_private *i915)
+{
+       struct pci_dev *pdev = i915->drm.pdev;
+
+       /* IGP is 0000:00:02.0 */
+       return pci_domain_nr(pdev->bus) == 0 &&
+              pdev->bus->number == 0 &&
+              PCI_SLOT(pdev->devfn) == 2 &&
+              PCI_FUNC(pdev->devfn) == 0;
+}
+
 void i915_pmu_register(struct drm_i915_private *i915)
 {
        struct i915_pmu *pmu = &i915->pmu;
@@ -1110,10 +1121,19 @@ void i915_pmu_register(struct drm_i915_private *i915)
        hrtimer_init(&pmu->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        pmu->timer.function = i915_sample;
 
-       ret = perf_pmu_register(&pmu->base, "i915", -1);
-       if (ret)
+       if (!is_igp(i915))
+               pmu->name = kasprintf(GFP_KERNEL,
+                                     "i915-%s",
+                                     dev_name(i915->drm.dev));
+       else
+               pmu->name = "i915";
+       if (!pmu->name)
                goto err;
 
+       ret = perf_pmu_register(&pmu->base, pmu->name, -1);
+       if (ret)
+               goto err_name;
+
        ret = i915_pmu_register_cpuhp_state(pmu);
        if (ret)
                goto err_unreg;
@@ -1122,6 +1142,9 @@ void i915_pmu_register(struct drm_i915_private *i915)
 
 err_unreg:
        perf_pmu_unregister(&pmu->base);
+err_name:
+       if (!is_igp(i915))
+               kfree(pmu->name);
 err:
        pmu->base.event_init = NULL;
        free_event_attributes(pmu);
@@ -1143,5 +1166,7 @@ void i915_pmu_unregister(struct drm_i915_private *i915)
 
        perf_pmu_unregister(&pmu->base);
        pmu->base.event_init = NULL;
+       if (!is_igp(i915))
+               kfree(pmu->name);
        free_event_attributes(pmu);
 }

diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h
index 067dbbf..bf52e39 100644 (file)
--- a/drivers/gpu/drm/i915/i915_pmu.h
+++ b/drivers/gpu/drm/i915/i915_pmu.h
@@ -47,6 +47,10 @@ struct i915_pmu {
         */
        struct pmu base;
        /**
+        * @name: Name as registered with perf core.
+        */
+       const char *name;
+       /**
         * @lock: Lock protecting enable mask and ref count handling.
         */
        spinlock_t lock;