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

[Rob Herring <robh@kernel.org>]

On Wed, Dec 13, 2023 at 12:17:17PM +0100, 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@mediatek.com>
> > > ---
> > >   .../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.

Or rx-fifo-size. There's so many to choose from.

Rob