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 3k bytes; The side-effect is that may cause performance drop about 10%, including bulk transfer. Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> --- v3: add fifo depth unit, change the value range from 0-3 to 1-4 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..9478b7031796 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 3 here. The unit is 1K bytes. + minimum: 1 + maximum: 4 + # the following properties are only used for case 1 wakeup-source: description: enable USB remote wakeup, see power/wakeup-source.txt -- 2.18.0