Il 20/12/23 08:38, Krzysztof Kozlowski ha scritto:
On 20/12/2023 03:58, 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 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.
NAK. Read comments on previous submission.
Best regards,
Krzysztof
Chunfeng, I think the discussion was not clear for you, so I will try to give
you a different explanation: this should be expressed in bytes, so 1000, or 1024,
2048, 4096, etc, and not 1/2/3/4/5/n.
The driver shall then validate and map your bytes number to hardware register
value and subsequently write to the registers.
Cheers,
Angleo
