Re: [PATCH 3/4] perf/dwc_pcie: Always register for PCIe bus notifier

On 8/15/2024 7:19 PM, Yicong Yang wrote:

On 2024/7/31 12:23, Krishna chaitanya chundru wrote:

quoted

When the PCIe devices are discovered late, the driver can't find
the PCIe devices and returns in the init without registering with
the bus notifier. Due to that the devices which are discovered late
the driver can't register for this.

Register for bus notifier even if the device is not found in init.

Fixes: af9597adc2f1 ("drivers/perf: add DesignWare PCIe PMU driver")
Signed-off-by: Krishna chaitanya chundru <redacted>
---
  drivers/perf/dwc_pcie_pmu.c | 10 +++++-----
  1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/perf/dwc_pcie_pmu.c b/drivers/perf/dwc_pcie_pmu.c
index c115348b8d53..aa1010b44bcb 100644
--- a/drivers/perf/dwc_pcie_pmu.c
+++ b/drivers/perf/dwc_pcie_pmu.c

@@ -741,8 +741,6 @@ static int __init dwc_pcie_pmu_init(void)
  
  		found = true;
  	}
-	if (!found)
-		return -ENODEV;
  
  	ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
  				      "perf/dwc_pcie_pmu:online",

@@ -753,9 +751,11 @@ static int __init dwc_pcie_pmu_init(void)
  
  	dwc_pcie_pmu_hp_state = ret;
  
-	ret = platform_driver_register(&dwc_pcie_pmu_driver);
-	if (ret)
-		goto platform_driver_register_err;
+	if (!found) {
+		ret = platform_driver_register(&dwc_pcie_pmu_driver);
+		if (ret)
+			goto platform_driver_register_err;
+	}

This doesn't match the commit.

quoted

If any device is found at this stage, we cannot use them since you don't

register a driver.

If the device is not found then only we are skipping platform driver
register otherwise driver will be registering with the platform driver.

- Krishna Chaitanya.

quoted

  	ret = bus_register_notifier(&pci_bus_type, &dwc_pcie_pmu_nb);
  	if (ret)