From: Kyle Meyer <[email protected]>
Revert part of commit 75c0758137c7a
("acpi-cpufreq: Fail initialization if driver cannot be registered").
acpi-cpufreq is mutually exclusive with intel_pstate, however,
acpi-cpufreq is loaded multiple times during startup while intel_pstate is
enabled. On systems using systemd the kernel triggers one uevent for each
device as a result of systemd-udev-trigger.service. The service exists to
retrigger all devices as uevents sent by the kernel before systemd-udevd
is running are missed. The delay caused by systemd-udevd repeatedly loading
the driver, getting a fail return, and unloading the driver twice per
logical CPU has a significant impact on the startup time, and can cause
some devices to be unavailable after reaching the root login prompt.
Load the driver once but skip initialization if a cpufreq driver exists by
changing the return value of cpufreq_get_current_driver() from -EEXIST to
0.
Signed-off-by: Kyle Meyer <[email protected]>
---
drivers/cpufreq/acpi-cpufreq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 7e7450453714..e79a945369d1 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -1003,7 +1003,7 @@ static int __init acpi_cpufreq_init(void)
/* don't keep reloading if cpufreq_driver exists */
if (cpufreq_get_current_driver())
- return -EEXIST;
+ return 0;
pr_debug("%s\n", __func__);
--
2.26.2
On Tuesday, May 18, 2021 9:34:55 PM CEST [email protected] wrote:
> From: Kyle Meyer <[email protected]>
>
> Revert part of commit 75c0758137c7a
> ("acpi-cpufreq: Fail initialization if driver cannot be registered").
>
> acpi-cpufreq is mutually exclusive with intel_pstate, however,
> acpi-cpufreq is loaded multiple times during startup while intel_pstate is
> enabled. On systems using systemd the kernel triggers one uevent for each
> device as a result of systemd-udev-trigger.service. The service exists to
> retrigger all devices as uevents sent by the kernel before systemd-udevd
> is running are missed. The delay caused by systemd-udevd repeatedly loading
> the driver, getting a fail return, and unloading the driver twice per
> logical CPU has a significant impact on the startup time, and can cause
> some devices to be unavailable after reaching the root login prompt.
>
> Load the driver once but skip initialization if a cpufreq driver exists by
> changing the return value of cpufreq_get_current_driver() from -EEXIST to
> 0.
>
> Signed-off-by: Kyle Meyer <[email protected]>
> ---
> drivers/cpufreq/acpi-cpufreq.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
> index 7e7450453714..e79a945369d1 100644
> --- a/drivers/cpufreq/acpi-cpufreq.c
> +++ b/drivers/cpufreq/acpi-cpufreq.c
> @@ -1003,7 +1003,7 @@ static int __init acpi_cpufreq_init(void)
>
> /* don't keep reloading if cpufreq_driver exists */
> if (cpufreq_get_current_driver())
> - return -EEXIST;
> + return 0;
>
> pr_debug("%s\n", __func__);
>
>
Please resend this with CCs to [email protected] and [email protected].
Thanks!