Re: [PATCH v2] USB: uas: Add the no-UAS quirk for JMicron JMS561U

From: Hans de Goede <hdegoede@redhat.com>
To: Tim Schumacher <timschumi@gmx.de>
Cc: stern@rowland.harvard.edu, linux-usb@vger.kernel.org,
	stable@vger.kernel.org
Subject: Re: [PATCH v2] USB: uas: Add the no-UAS quirk for JMicron JMS561U
Date: Sat, 25 Jan 2020 19:37:00 +0100	[thread overview]
Message-ID: <fccf2105-d415-7f44-e111-729d2d517ea7@redhat.com> (raw)
In-Reply-To: <20200125170030.25331-1-timschumi@gmx.de>

Hi,

On 1/25/20 6:00 PM, Tim Schumacher wrote:
> The JMicron JMS561U (notably used in the Sabrent SATA-to-USB
> bridge) appears to have UAS-related issues when copying large
> amounts of data, causing it to stall.
> 
> Disabling the advertised UAS (either through a command-line
> quirk or through this patch) mitigates those issues.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Tim Schumacher <timschumi@gmx.de>

Hmm, this is a quiete popular usb2sata bridge and disabling uas
is quite bad for performance.

I notice that there is no link to a bug report and AFAIK we have
no one else reporting this issue.

So this feels like a much too big hammer for the problem which you
are seeing.

When you say "stall" what exactly happens? Do you see any errors
in dmesg for example?

Also note that using UAS, since it has much better performance,
will often expose bugs which are not caused by it. One typical
example is bus-powered devices where the USB port does not deliver
enough power (typically the driver draws more then the port
guanrantees). Copying large amounts of data on a fast device is
a good way to make the current consumption go up and thus
trigger these kind of issues.  Does the driver enclosure
you see this on use a separate power supply, or is it
bus-powered?

Regards,

Hans

> ---
> v2: Fixed entry order. Also, CCing the correct people now.
> ---
>   drivers/usb/storage/unusual_uas.h | 7 +++++++
>   1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/usb/storage/unusual_uas.h b/drivers/usb/storage/unusual_uas.h
> index 1b23741036ee..a590f4a0d4b9 100644
> --- a/drivers/usb/storage/unusual_uas.h
> +++ b/drivers/usb/storage/unusual_uas.h
> @@ -73,6 +73,13 @@ UNUSUAL_DEV(0x152d, 0x0578, 0x0000, 0x9999,
>   		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
>   		US_FL_BROKEN_FUA),
> 
> +/* Reported-by: Tim Schumacher <timschumi@gmx.de> */
> +UNUSUAL_DEV(0x152d, 0x1561, 0x0000, 0x9999,
> +		"JMicron",
> +		"JMS561U",
> +		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
> +		US_FL_IGNORE_UAS),
> +
>   /* Reported-by: Hans de Goede <hdegoede@redhat.com> */
>   UNUSUAL_DEV(0x2109, 0x0711, 0x0000, 0x9999,
>   		"VIA",
> --
> 2.25.0
> 