Re: [PATCH 1/3] dt-bindings: usb: mtk-xhci: add a property for Gen1 isoc-in transfer issue

From: Krzysztof Kozlowski
Date: Wed Dec 13 2023 - 03:06:03 EST


On 13/12/2023 07:35, Chunfeng Yun wrote:
> For Gen1 isoc-in endpoint on controller before about SSUSB IPM v1.6.0, it
> still send out unexpected ACK after receiving a short packet in burst
> transfer, this will cause an exception on connected device, specially for
> a 4k camera.
> Add a quirk property "mediatek,rxfifo-depth" to work around this hardware
> issue;
> The side-effect is that may cause performance drop about 10%, including
> bulk transfer.
>
> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> ---
> .../devicetree/bindings/usb/mediatek,mtk-xhci.yaml | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
> index e9644e333d78..b8ed68574ba4 100644
> --- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
> +++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml
> @@ -124,6 +124,16 @@ properties:
> defined in the xHCI spec on MTK's controller.
> default: 5000
>
> + mediatek,rxfifo-depth:
> + description:

The property description and driver patch suggest you configure the
depth of FIFO, so this should be not bool, but some uint32. And then,
use generic "fifo-depth" property to set desired depth.


Best regards,
Krzysztof