Messages in this thread Patch in this message | | | Date | Thu, 23 Apr 2015 07:47:38 +0200 | From | Stephane Eranian <> | Subject | [PATCH] perf/x86/intel/uncore: fix IMC missing box initialization |
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This patch fixes a bug introduced by:
commit c05199e5a57a579fea1e8fa65e2b511ceb524ffc Author: Kan Liang <kan.liang@intel.com> Date: Tue Jan 20 04:54:25 2015 +0000
perf/x86/intel/uncore: Move uncore_box_init() out of driver initialization
It moves uncore_box_init() out of place but this meant that for desktop memory controller (IMC) PCI-based PMU, the intialization was now missing causing a crash at first access. This patch fixes the issue by adding the call to the uncore_enable_box() in snb_uncore_imc_read_counter() to ensure the box is initialized and the PCI BAR is io-remapped.
Signed-off-by: Stephane Eranian <eranian@google.com> --
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c b/arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c index 4562e9e..755ec05 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore_snb.c @@ -329,6 +329,9 @@ static void snb_uncore_imc_event_start(struct perf_event *event, int flags) list_add_tail(&event->active_entry, &box->active_list); + if (box->n_active == 1) + uncore_enable_box(box); + count = snb_uncore_imc_read_counter(box, event); local64_set(&event->hw.prev_count, count);
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