Re: [PATCH] Revert "ACPI: power: Turn off unused power resources unconditionally"

From: Rafael J. Wysocki
Date: Fri Apr 30 2021 - 09:32:10 EST


On Fri, Apr 30, 2021 at 2:43 PM Shujun Wang <wsj20369@xxxxxxx> wrote:
>
> This reverts commit 7e4fdeafa61f2b653fcf9678f09935e55756aed2.

OK, I'll revert that commit, thanks!

> It may cause some NVMe device probes to fail, and the system may get
> stuck when using an NVMe device as the root filesystem.
>
> In the function nvme_pci_enable(struct nvme_dev *dev), as shown below,
> readl(NVME_REG_CSTS) always returns -1 with the commit, which results in
> the probe failed.
>
> if (readl(dev->bar + NVME_REG_CSTS) == -1) {
> result = -ENODEV;
> goto disable;
> }
>
> dmesg:
> [ 1.106280] nvme 0000:04:00.0: platform quirk: setting simple suspend
> [ 1.109111] nvme nvme0: pci function 0000:04:00.0
> [ 1.113066] nvme 0000:04:00.0: enabling device (0000 -> 0002)
> [ 1.121040] nvme nvme0: Removing after probe failure status: -19
>
> lspci:
> Non-Volatile memory controller: KIOXIA Corporation Device 0001
>
> device uevent:
> DRIVER=nvme
> PCI_CLASS=10802
> PCI_ID=1E0F:0001
> PCI_SUBSYS_ID=1E0F:0001
> PCI_SLOT_NAME=0000:04:00.0
> MODALIAS=pci:v00001E0Fd00000001sv00001E0Fsd00000001bc01sc08i02
>
> This patch was tested in Lenovo Thinkpad X1.
>
> Signed-off-by: Shujun Wang <wsj20369@xxxxxxx>
> ---
> drivers/acpi/power.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
> index 56102eaaa2da..8bf10abeb2e0 100644
> --- a/drivers/acpi/power.c
> +++ b/drivers/acpi/power.c
> @@ -1004,9 +1004,18 @@ void acpi_turn_off_unused_power_resources(void)
> mutex_lock(&power_resource_list_lock);
>
> list_for_each_entry_reverse(resource, &acpi_power_resource_list, list_node) {
> + int result, state;
> +
> mutex_lock(&resource->resource_lock);
>
> - if (!resource->ref_count) {
> + result = acpi_power_get_state(resource->device.handle, &state);
> + if (result) {
> + mutex_unlock(&resource->resource_lock);
> + continue;
> + }
> +
> + if (state == ACPI_POWER_RESOURCE_STATE_ON
> + && !resource->ref_count) {
> dev_info(&resource->device.dev, "Turning OFF\n");
> __acpi_power_off(resource);
> }
> --
> 2.25.1
>