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Message-ID: <20231220025842.7082-1-chunfeng.yun@mediatek.com>
Date: Wed, 20 Dec 2023 10:58:40 +0800
From: Chunfeng Yun <chunfeng.yun@...iatek.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Rob Herring
<robh+dt@...nel.org>, Krzysztof Kozlowski
<krzysztof.kozlowski+dt@...aro.org>, AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>
CC: Chunfeng Yun <chunfeng.yun@...iatek.com>, Conor Dooley
<conor+dt@...nel.org>, Matthias Brugger <matthias.bgg@...il.com>, "Mathias
Nyman" <mathias.nyman@...el.com>, <linux-usb@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <linux-mediatek@...ts.infradead.org>,
<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Eddie Hung
<eddie.hung@...iatek.com>, Macpaul Lin <macpaul.lin@...iatek.com>
Subject: [PATCH v3 1/3] dt-bindings: usb: mtk-xhci: add a property for Gen1 isoc-in transfer issue
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@...iatek.com>
---
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.
+ minimum: 1
+ maximum: 4
+
# the following properties are only used for case 1
wakeup-source:
description: enable USB remote wakeup, see power/wakeup-source.txt
--
2.18.0
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