From cd2a6747583b441ad898834d3dd246ed271ad35d Mon Sep 17 00:00:00 2001 From: Prashanth K Date: Tue, 31 Dec 2024 13:41:09 +0530 Subject: [PATCH] arm64: dts: qcom: sdx75: Disable USB U1/U2 entry Disable U1 and U2 power-saving states to improve stability of USB. These low-power link states, designed to reduce power consumption during idle periods, can cause issues in latency-sensitive or high throughput use cases. Over the years, some of the issues seen are as follows: 1. In device mode of operation, when UVC is active, enabling U1/U2 is sometimes causing packets drops due to delay in entry/exit of intermittent these low power states. These packet drops are often reflected as missed isochronous transfers, as the controller wasn't able to send packet in that microframe interval and hence glitches are seen on the final transmitted video output. 2. On older targets like SM8150/SM8250/SM8350, there have been throughput issues seen during tethering use cases. 3. On targets like SDX75, intermittent disconnects were observed with certain cables due to impedence variations. Disabling these intermittent power states enhances device stability without affecting power usage. Signed-off-by: Prashanth K Reviewed-by: Konrad Dybcio Link: https://lore.kernel.org/r/20241231081115.3149850-12-quic_prashk@quicinc.com Signed-off-by: Bjorn Andersson --- arch/arm64/boot/dts/qcom/sdx75.dtsi | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/boot/dts/qcom/sdx75.dtsi b/arch/arm64/boot/dts/qcom/sdx75.dtsi index 68d7dbe037b6..06d956f5cd4e 100644 --- a/arch/arm64/boot/dts/qcom/sdx75.dtsi +++ b/arch/arm64/boot/dts/qcom/sdx75.dtsi @@ -1037,6 +1037,8 @@ iommus = <&apps_smmu 0x80 0x0>; snps,dis_u2_susphy_quirk; snps,dis_enblslpm_quirk; + snps,dis-u1-entry-quirk; + snps,dis-u2-entry-quirk; phys = <&usb_hsphy>, <&usb_qmpphy>; phy-names = "usb2-phy", -- 2.50.1