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

[Krzysztof Kozlowski]

On 13/12/2023 12:17, AngeloGioacchino Del Regno wrote:
> Il 13/12/23 09:05, Krzysztof Kozlowski ha scritto:
>> 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.
> 
> Did you mean "rx-fifo-depth" instead, as used in net?
> This FIFO depth parameter is for RX only.

I guess yes, if it is specific to RX.

Best regards,
Krzysztof