Hi, On 1/15/21 11:43 PM, Pierre-Louis Bossart wrote: >>> OK, thanks! >>> >>> Now, there is a theory to test and some more debug work to do. >>> >>> First, the kernel should not crash outright if some ACPI device objects are >>> missing which evidently happens here. There may be some problems resulting >>> from that, but the crash indicates a code bug in the kernel. >>> >>> Apparently, something expects the device objects to be there so badly, that it >>> crashes right away when they aren't there. One of the issues that may cause >>> that to happen are mistakes around the acpi_bus_get_device() usage and I found >>> two of them, so below is a patch to test. >>> >>> Please apply to plain 5.11-rc3 (or -rc4 when it is out) and see if that makes >>> any difference. >>> >>> --- >>> drivers/acpi/scan.c | 3 +-- >>> drivers/usb/core/usb-acpi.c | 3 +-- >>> 2 files changed, 2 insertions(+), 4 deletions(-) >>> >>> Index: linux-pm/drivers/acpi/scan.c >>> =================================================================== >>> --- linux-pm.orig/drivers/acpi/scan.c >>> +++ linux-pm/drivers/acpi/scan.c >>> @@ -2120,8 +2120,7 @@ void acpi_walk_dep_device_list(acpi_hand >>> mutex_lock(&acpi_dep_list_lock); >>> list_for_each_entry_safe(dep, tmp, &acpi_dep_list, node) { >>> if (dep->supplier == handle) { >>> - acpi_bus_get_device(dep->consumer, &adev); >>> - if (!adev) >>> + if (acpi_bus_get_device(dep->consumer, &adev)) >>> continue; >>> >>> adev->dep_unmet--; >>> Index: linux-pm/drivers/usb/core/usb-acpi.c >>> =================================================================== >>> --- linux-pm.orig/drivers/usb/core/usb-acpi.c >>> +++ linux-pm/drivers/usb/core/usb-acpi.c >>> @@ -163,10 +163,9 @@ usb_acpi_get_companion_for_port(struct u >>> } else { >>> parent_handle = usb_get_hub_port_acpi_handle(udev->parent, >>> udev->portnum); >>> - if (!parent_handle) >>> + if (!parent_handle || acpi_bus_get_device(parent_handle, &adev)) >>> return NULL; >>> >>> - acpi_bus_get_device(parent_handle, &adev); >>> port1 = port_dev->portnum; >>> } >>> >> I can confirm that these changes fix the intermittent boot issue I had with >> 5.11-rc3 on the Minix Neo z83-4. It is getting a bit late here, so I will >> test my second (also intermittent) reproducer tomorrow. > > Success on my side as well. I can boot and here is the updated list of dependencies (shorter than for the last test) It is shorter because of this part of the debugging patch which Rafael send: --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -1854,7 +1854,8 @@ static u32 acpi_scan_check_dep(acpi_handle handle) * 2. ACPI nodes describing USB ports. * Still, checking for _HID catches more then just these cases ... */ - if (!acpi_has_method(handle, "_DEP") || !acpi_has_method(handle, "_HID")) + if (!acpi_has_method(handle, "_DEP") || acpi_has_method(handle, "_ADR") + || !acpi_has_method(handle, "_HID")) return 0; status = acpi_evaluate_reference(handle, "_DEP", NULL, &dep_devices); So that is expected. > I attached the diff I tested to make sure I didn't miss anything. Erm, it looks like you also applied the debug patch from Rafael's last email, that was only intended to be applied in case things still did not work I believe. This bit from the debug-patch: @@ -1937,10 +1938,8 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, bool check_dep, if (type == ACPI_BUS_TYPE_DEVICE && check_dep) { u32 count = acpi_scan_check_dep(handle); /* Bail out if the number of recorded dependencies is not 0. */ - if (count > 0) { - acpi_bus_scan_second_pass = true; - return AE_CTRL_DEPTH; - } + if (count > 0) + acpi_handle_info(handle, "Dependencies found\n"); } acpi_add_single_object(&device, handle, type, sta); Will cause all devices to be added during the first scan pass, like my initial hack/test patch. Can you drop the debug patch and test with just the 2 changes from Rafael's previous mail please ? Regards, Hans > > Thanks > > -Pierre > >