Re: [PATCH] arm64: dts: qcom: glymur: Mark USB controllers dma-coherent

From: Gopikrishna Garmidi

Date: Thu Aug 13 2026 - 01:44:41 EST




On 8/12/2026 9:10 PM, Greg Ociepka wrote:
All five USB controller nodes on Glymur (usb_0, usb_1, usb_2, usb_hs,
usb_mp) are missing the dma-coherent property, which Hamoa carries on
all of its USB controllers. Krishna Kurapati confirmed the Glymur USB
controllers are dma-coherent [1].

Without the property the kernel treats USB DMA buffers as non-coherent
and performs cache maintenance on every transfer, which coherent
hardware makes redundant.

Follow-up to the clock/power/bandwidth votes patch [2], kept separate
so the already-reviewed patch stands as is.

Tested on an Asus Zenbook A16 (UX3607OA): all controllers enumerate
their devices as before and a 64 MiB write plus two O_DIRECT
read-backs over USB mass storage produce identical checksums.

[1] https://lore.kernel.org/linux-arm-msm/f92cc91e-6e5c-4375-aaa6-f079a165f4b5@xxxxxxxxxxxxxxxx/
[2] https://lore.kernel.org/linux-arm-msm/20260812083522.774711-1-greg@xxxxxxxxxxxxx/

Fixes: 4eee57dd4df9 ("arm64: dts: qcom: glymur: Add USB related nodes")
Signed-off-by: Greg Ociepka <greg@xxxxxxxxxxxxx>
Assisted-by: Claude:fable-5
Reviewed-by: Gopikrishna Garmidi <gopikrishna.garmidi@xxxxxxxxxxxxxxxx>