* [PATCH v4 1/2] dt-bindings: usb: add "hub,interval" property
@ 2019-12-03 10:15 Ikjoon Jang
2019-12-16 15:38 ` Rob Herring
0 siblings, 1 reply; 2+ messages in thread
From: Ikjoon Jang @ 2019-12-03 10:15 UTC (permalink / raw)
To: devicetree
Cc: GregKroah-Hartman, RobHerring, MarkRutland, AlanStern, SuwanKim,
GustavoA . R . Silva, IkjoonJang, JohanHovold, linux-usb,
linux-kernel, drinkcat
Add "hub,interval" property to usb-device, so hub device can override
endpoint descriptor's bInterval.
When we know reducing autosuspend delay for built-in HIDs is better for
power saving, we can reduce it to the optimal value. But if a parent hub
has a long bInterval, mouse lags a lot from more frequent autosuspend.
So this enables overriding bInterval for a hard wired hub device only
when we know that reduces the power consumption.
Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
---
Documentation/devicetree/bindings/usb/usb-device.txt | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/Documentation/devicetree/bindings/usb/usb-device.txt b/Documentation/devicetree/bindings/usb/usb-device.txt
index 036be172b1ae..44bef2ff2704 100644
--- a/Documentation/devicetree/bindings/usb/usb-device.txt
+++ b/Documentation/devicetree/bindings/usb/usb-device.txt
@@ -66,6 +66,9 @@ Required properties for host-controller nodes with device nodes:
- #size-cells: shall be 0
+Optional properties for hub nodes
+- hub,interval: bInterval of status change endpoint. The range is 1-255.
+
Example:
&usb1 { /* host controller */
@@ -75,6 +78,7 @@ Example:
hub@1 { /* hub connected to port 1 */
compatible = "usb5e3,608";
reg = <1>;
+ hub,interval = <8>;
};
device@2 { /* device connected to port 2 */
--
2.24.0.393.g34dc348eaf-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v4 1/2] dt-bindings: usb: add "hub,interval" property
2019-12-03 10:15 [PATCH v4 1/2] dt-bindings: usb: add "hub,interval" property Ikjoon Jang
@ 2019-12-16 15:38 ` Rob Herring
0 siblings, 0 replies; 2+ messages in thread
From: Rob Herring @ 2019-12-16 15:38 UTC (permalink / raw)
To: Ikjoon Jang
Cc: devicetree, GregKroah-Hartman, MarkRutland, AlanStern, SuwanKim,
GustavoA . R . Silva, JohanHovold, linux-usb, linux-kernel,
drinkcat
On Tue, Dec 03, 2019 at 06:15:36PM +0800, Ikjoon Jang wrote:
> Add "hub,interval" property to usb-device, so hub device can override
> endpoint descriptor's bInterval.
>
> When we know reducing autosuspend delay for built-in HIDs is better for
> power saving, we can reduce it to the optimal value. But if a parent hub
> has a long bInterval, mouse lags a lot from more frequent autosuspend.
> So this enables overriding bInterval for a hard wired hub device only
> when we know that reduces the power consumption.
>
> Signed-off-by: Ikjoon Jang <ikjn@chromium.org>
> ---
> Documentation/devicetree/bindings/usb/usb-device.txt | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/usb/usb-device.txt b/Documentation/devicetree/bindings/usb/usb-device.txt
> index 036be172b1ae..44bef2ff2704 100644
> --- a/Documentation/devicetree/bindings/usb/usb-device.txt
> +++ b/Documentation/devicetree/bindings/usb/usb-device.txt
> @@ -66,6 +66,9 @@ Required properties for host-controller nodes with device nodes:
> - #size-cells: shall be 0
>
>
> +Optional properties for hub nodes
> +- hub,interval: bInterval of status change endpoint. The range is 1-255.
'hub' is not a vendor.
'b-interval' instead.
Rob
^ permalink raw reply [flat|nested] 2+ messages in thread
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