* [PATCH 1/2] usb: ehci-pci: Set PROBE_PREFER_ASYNCHRONOUS
@ 2022-10-28 21:19 Brian Norris
2022-10-28 21:19 ` [PATCH 2/2] usb: xhci-pci: " Brian Norris
2022-10-29 1:13 ` [PATCH 1/2] usb: ehci-pci: " Alan Stern
0 siblings, 2 replies; 4+ messages in thread
From: Brian Norris @ 2022-10-28 21:19 UTC (permalink / raw)
To: Alan Stern, Greg Kroah-Hartman, Mathias Nyman
Cc: Brian Norris, linux-kernel, linux-usb
This driver often takes on the order of 8ms to start, but every little
bit counts. It shouldn't have many cross-device dependencies to
race with, nor racy access to shared state with other drivers, so this
should be a relatively low risk change.
This driver was pinpointed as part of a survey of top slowest initcalls
(i.e., are built in, and probing synchronously) on a lab of ChromeOS
systems.
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
drivers/usb/host/ehci-pci.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index 17f8b6ea0c35..4b148fe5e43b 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/drivers/usb/host/ehci-pci.c
@@ -411,11 +411,12 @@ static struct pci_driver ehci_pci_driver = {
.remove = ehci_pci_remove,
.shutdown = usb_hcd_pci_shutdown,
-#ifdef CONFIG_PM
.driver = {
- .pm = &usb_hcd_pci_pm_ops
- },
+#ifdef CONFIG_PM
+ .pm = &usb_hcd_pci_pm_ops,
#endif
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ },
};
static int __init ehci_pci_init(void)
--
2.38.1.273.g43a17bfeac-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 2/2] usb: xhci-pci: Set PROBE_PREFER_ASYNCHRONOUS
2022-10-28 21:19 [PATCH 1/2] usb: ehci-pci: Set PROBE_PREFER_ASYNCHRONOUS Brian Norris
@ 2022-10-28 21:19 ` Brian Norris
2022-10-29 1:13 ` [PATCH 1/2] usb: ehci-pci: " Alan Stern
1 sibling, 0 replies; 4+ messages in thread
From: Brian Norris @ 2022-10-28 21:19 UTC (permalink / raw)
To: Alan Stern, Greg Kroah-Hartman, Mathias Nyman
Cc: Brian Norris, linux-kernel, linux-usb
This driver often takes on the order of 10ms to start, but in some cases
takes more than 100ms. It shouldn't have many cross-device dependencies
to race with, nor racy access to shared state with other drivers, so
this should be a relatively low risk change.
This driver was pinpointed as part of a survey of top slowest initcalls
(i.e., are built in, and probing synchronously) on a lab of ChromeOS
systems.
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
drivers/usb/host/xhci-pci.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 40228a3d77a0..4da03de1be70 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -689,7 +689,8 @@ static struct pci_driver xhci_pci_driver = {
.shutdown = usb_hcd_pci_shutdown,
#ifdef CONFIG_PM
.driver = {
- .pm = &usb_hcd_pci_pm_ops
+ .pm = &usb_hcd_pci_pm_ops,
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
},
#endif
};
--
2.38.1.273.g43a17bfeac-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] usb: ehci-pci: Set PROBE_PREFER_ASYNCHRONOUS
2022-10-28 21:19 [PATCH 1/2] usb: ehci-pci: Set PROBE_PREFER_ASYNCHRONOUS Brian Norris
2022-10-28 21:19 ` [PATCH 2/2] usb: xhci-pci: " Brian Norris
@ 2022-10-29 1:13 ` Alan Stern
2022-10-29 1:44 ` Brian Norris
1 sibling, 1 reply; 4+ messages in thread
From: Alan Stern @ 2022-10-29 1:13 UTC (permalink / raw)
To: Brian Norris; +Cc: Greg Kroah-Hartman, Mathias Nyman, linux-kernel, linux-usb
On Fri, Oct 28, 2022 at 02:19:07PM -0700, Brian Norris wrote:
> This driver often takes on the order of 8ms to start, but every little
> bit counts. It shouldn't have many cross-device dependencies to
> race with, nor racy access to shared state with other drivers, so this
> should be a relatively low risk change.
>
> This driver was pinpointed as part of a survey of top slowest initcalls
> (i.e., are built in, and probing synchronously) on a lab of ChromeOS
> systems.
>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
Acked-by: Alan Stern <stern@rowland.harvard.edu>
However, I'm curious to know why this patch makes ehci-pci use
PROBE_PREFER_ASYNCHRONOUS even when CONFIG_PM isn't set, whereas the 2/2
patch makes xhci-pci use PROBE_PREFER_ASYNCHRONOUS only when CONFIG_PM
is set.
Alan Stern
> drivers/usb/host/ehci-pci.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
> index 17f8b6ea0c35..4b148fe5e43b 100644
> --- a/drivers/usb/host/ehci-pci.c
> +++ b/drivers/usb/host/ehci-pci.c
> @@ -411,11 +411,12 @@ static struct pci_driver ehci_pci_driver = {
> .remove = ehci_pci_remove,
> .shutdown = usb_hcd_pci_shutdown,
>
> -#ifdef CONFIG_PM
> .driver = {
> - .pm = &usb_hcd_pci_pm_ops
> - },
> +#ifdef CONFIG_PM
> + .pm = &usb_hcd_pci_pm_ops,
> #endif
> + .probe_type = PROBE_PREFER_ASYNCHRONOUS,
> + },
> };
>
> static int __init ehci_pci_init(void)
> --
> 2.38.1.273.g43a17bfeac-goog
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] usb: ehci-pci: Set PROBE_PREFER_ASYNCHRONOUS
2022-10-29 1:13 ` [PATCH 1/2] usb: ehci-pci: " Alan Stern
@ 2022-10-29 1:44 ` Brian Norris
0 siblings, 0 replies; 4+ messages in thread
From: Brian Norris @ 2022-10-29 1:44 UTC (permalink / raw)
To: Alan Stern; +Cc: Greg Kroah-Hartman, Mathias Nyman, linux-kernel, linux-usb
On Fri, Oct 28, 2022 at 09:13:14PM -0400, Alan Stern wrote:
> However, I'm curious to know why this patch makes ehci-pci use
> PROBE_PREFER_ASYNCHRONOUS even when CONFIG_PM isn't set, whereas the 2/2
> patch makes xhci-pci use PROBE_PREFER_ASYNCHRONOUS only when CONFIG_PM
> is set.
That's definitely a bug in patch 2. This has nothing (or, little; probe
order can technically affect the PM suspend/resume order) to do with
CONFIG_PM, except that the .pm hooks tend to sit nearby, and repeated
driver patching makes the author's eyes glaze over sometimes...
Thanks. v2 coming.
Brian
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-10-29 1:44 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-10-28 21:19 [PATCH 1/2] usb: ehci-pci: Set PROBE_PREFER_ASYNCHRONOUS Brian Norris
2022-10-28 21:19 ` [PATCH 2/2] usb: xhci-pci: " Brian Norris
2022-10-29 1:13 ` [PATCH 1/2] usb: ehci-pci: " Alan Stern
2022-10-29 1:44 ` Brian Norris
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