On 2025/3/11 00:49, Shuah Khan wrote:
On 3/5/25 03:03, Zongmin Zhou wrote:If set vhci-hcd dma mask to 64 by default,I can't predict what will happen when the real USB controller support less than 64bit?
At 2025-03-05 03:45:28, "Shuah Khan" <skhan@xxxxxxxxxxxxxxxxxxx> wrote:
On 3/2/25 05:37, Zongmin Zhou wrote:>What are the two possible solutions?
Dear shuah,
Yes, I agree with you.It would be better if there have a more simpler fixes than This patch.
I can just think of the two possible solutions that mentioned before.
1. The patch we are discussing now,have to change the API between the kernel and user-space.
2. Simply set vhci-hcd dma mask to 64 by default,just modify the vhci-hcd driver. Then dma_max_mapping_size() will always return SIZE_MAX.
I prefer option #2 - What are the downsides if any with this option?
After all, the data flows from vhci-hcd to usbip-host and finally to the USB controller to which the device is actually connected.
the data is ultimately processed through the real USB controller?
However, the default setting to 64-bit is equivalent to eliminating the impact of
the patch(commit d74ffae8b8dd) on usbip protocol devices, sounds feasible?
I am not very professional in this field, waiting for your evaluation.