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 it may cause performance drop about 10%, including bulk transfer. Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx> --- v5: fix typos, add acked-by and reviewed-by v4: change rx-fifo size in bytes 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 | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml index e9644e333d78..924fd3d748a8 100644 --- a/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml +++ b/Documentation/devicetree/bindings/usb/mediatek,mtk-xhci.yaml @@ -124,6 +124,17 @@ 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 finishes 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 it may cause performance drop about 10%, + including bulk transfer, prefer to use 3k here. The size is in bytes. + enum: [1024, 2048, 3072, 4096] + # the following properties are only used for case 1 wakeup-source: description: enable USB remote wakeup, see power/wakeup-source.txt -- 2.18.0