Re: usb-storage & xhci_hcd & swiotlb buffer problem filling systemd with error during operation with SSD on USB3

On Thu, Jul 29, 2021 at 05:32:57PM +0200, Sébastien Rey-Coyrehourcq wrote:

 Hi,

This is my first bug report on kernel, first crossposted here (https://www.reddit.com/r/NixOS/comments/omctp3/rpi4_nixos_native_2105_and_ssd_by_usb3/)
and here on nixos github (https://github.com/NixOS/nixpkgs/issues/130499) :

[1.] One line summary of the problem:

Using an usb sata adaptater from Startech (USB312SAT3CB 3.1 firmware
upgraded) on my RPI4B 8gb with the kernel 5.13.4, during any dd=/ operation
on SSD on USB 3 port, my systemd logs finish full of errors of type :

juil. 29 14:38:52 Nostromo-sd kernel: xhci_hcd 0000:01:00.0: swiotlb buffer
is full (sz: 512 bytes), total 32768 (slots), used 32768 (slots)

and

juil. 29 09:25:07 Nostromo-sd kernel: ------------[ cut here ]------------
juil. 29 09:25:07 Nostromo-sd kernel: WARNING: CPU: 1 PID: 180 at
drivers/mmc/host/sdhci.c:1142 sdhci_prepare_data.isra.0+0x298/0x700

Your problem is in the sdhci code, not the usb controller.

But even with this, does the operation succeed properly?

The rpi hardware is HORRID when it comes to the USB controller, so those
xhci messages might just be normal given the lack of irq handling that
the platform was known to have in the past (note, might be better now,
no idea, sorry.)

But again, is the operation failing?  Is your sd card working properly?
Does the problem go away with a new/better sd card?

thanks,

greg k-h