On 20/12/2023 03:05, Chunfeng Yun (云春峰) wrote: > On Fri, 2023-12-15 at 08:36 +0100, Krzysztof Kozlowski wrote: >> >> External email : Please do not click links or open attachments until >> you have verified the sender or the content. >> 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? > 0 - 1K bytes; > 3 - 4K bytes; > I will add this in description No, don't add. Just use correct values. 0 means 0 words or bytes. Not 1000 bytes. Best regards, Krzysztof
