Re: [PATCH] usbip: set the dma mask to 64bit default for vhci-driver

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Apr 25, 2025 at 04:08:47PM +0800, Zongmin Zhou wrote:
> Dear Greg and Christoph:
> 
> This patch is the simple solution for the issue described in below link:
> https://lore.kernel.org/all/20250219092555.112631-1-min_halo@163.com/
> 
> This issue has been discussed at length with Shuah.
> 
> As Christoph said,vhci-hcd is a virtual hci,
> but it serves as a bridge to connect virtual USB devices to the real USB
> controller.
> Since the commit d74ffae8b8dd is applied on kernel v5.3,
> the virtual USB devices's max_sectors size is limited since v5.3.
> 
> Just because on vhci-hcd, the dma mask setting follows the platform device
> default setting(32-bit).

Wait, why is vhci-hcd a platform device at all?  It shouldn't be doing
that, try removing that to start with, which will remove that "default"
setting.  I recommend using the faux bus as a potential replacement.

thanks,

greg k-h