https://bugzilla.kernel.org/show_bug.cgi?id=201753 --- Comment #18 from Paul Menzel (pmenzel+bugzilla.kernel.org@xxxxxxxxxxxxx) --- Even with ten tries in the loop, it still fails with the AMD Ryzen 3 2200G with Radeon Vega Graphics (family: 0x17, model: 0x11, stepping: 0x0): [ 0.401152] pci 0000:00:00.2: AMD-Vi: Unable to read/write to IOMMU perf counter. (retry = 0) ``` diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c index 9126efcbaf2c7..70c00ee5ff354 100644 --- a/drivers/iommu/amd/init.c +++ b/drivers/iommu/amd/init.c @@ -1746,7 +1746,7 @@ static void __init init_iommu_perf_ctr(struct amd_iommu *iommu) /* Check if the performance counters can be written to */ val = 0xabcd; - for (retry = 5; retry; retry--) { + for (retry = 10; retry; retry--) { if (iommu_pc_get_set_reg(iommu, 0, 0, 0, &val, true) || iommu_pc_get_set_reg(iommu, 0, 0, 0, &val2, false) || val2) @@ -1764,7 +1764,7 @@ static void __init init_iommu_perf_ctr(struct amd_iommu *iommu) if (val != val2) goto pc_false; - pci_info(pdev, "IOMMU performance counters supported\n"); + pci_info(pdev, "IOMMU performance counters supported (retry = %i)\n", retry); val = readl(iommu->mmio_base + MMIO_CNTR_CONF_OFFSET); iommu->max_banks = (u8) ((val >> 12) & 0x3f); @@ -1773,7 +1773,7 @@ static void __init init_iommu_perf_ctr(struct amd_iommu *iommu) return; pc_false: - pci_err(pdev, "Unable to read/write to IOMMU perf counter.\n"); + pci_err(pdev, "Unable to read/write to IOMMU perf counter. (retry = %i)\n", retry); amd_iommu_pc_present = false; return; } ``` -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
