Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 7 Aug 2023 09:42:17 -0400
From:   Alan Stern <stern@rowland.harvard.edu>
To:     Piyush Mehta <piyush.mehta@amd.com>
Cc:     gregkh@linuxfoundation.org, michal.simek@amd.com,
        siva.durga.prasad.paladugu@amd.com, radhey.shyam.pandey@amd.com,
        git@amd.com, linux-usb@vger.kernel.org,
        usb-storage@lists.one-eyed-alien.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] uas: Add US_FL_NO_ATA_1X for linux tcm_usb_gadget
Message-ID: <3ff288b4-760c-4c8e-a8c2-a6cb4a1447ca@rowland.harvard.edu>
References: <20230807122025.2818062-1-piyush.mehta@amd.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230807122025.2818062-1-piyush.mehta@amd.com>
Precedence: bulk

On Mon, Aug 07, 2023 at 05:50:25PM +0530, Piyush Mehta wrote:
> The linux kernel's tcm_usb_gadget requires the US_FL_NO_ATA_1X quirk.
> It does not respond to the ATA_12 family of commands and hangs. The host

Are you certain of that?  Doesn't this depend on the underlying device 
that the gadget is attached to?

> prevents the issuing of ATA_12 commands to the TCM module, by introducing
> this quirk, the host is permitted to proceed with other operations.

Rather than changing just one host (the Linux one) while leaving all 
other hosts to malfunction, why not fix the gadget instead?  Change it 
so that it _doesn't_ hang when it gets an ATA_12 command but returns an 
appropriate error status.  That way the gadget will work with all hosts.

Alan Stern