On 15/12/2023 08:34, 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 "rx-fifo-depth" to work around this hardware issue, > prefer to use 2; > The side-effect is that may cause performance drop about 10%, including > bulk transfer. > > Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> > --- > v2: change 'mediatek,rxfifo-depth' to 'rx-fifo-depth' > --- > .../devicetree/bindings/usb/mediatek,mtk-xhci.yaml | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml > index e9644e333d78..e44a71acb5c0 100644 > --- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml > +++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml > @@ -124,6 +124,18 @@ properties: > defined in the xHCI spec on MTK's controller. > default: 5000 > > + rx-fifo-depth: > + $ref: /schemas/types.yaml#/definitions/uint32 > + description: > + It is a quirk used to work around Gen1 isoc-in endpoint transfer issue > + that still send out unexpected ACK after device finish the burst transfer > + with a short packet and cause an exception, specially on a 4K camera > + device, it happens on controller before about IPM v1.6.0; the side-effect > + is that may cause performance drop about 10%, include bulk transfer, > + prefer to use 2 here. What is the meaning of 0-3? bytes? words? > + minimum: 0 > + maximum: 3 Best regards, Krzysztof
