From: Alan Stern <stern@rowland.harvard.edu>
To: Badhri Jagan Sridharan <badhri@google.com>
Cc: gregkh@linuxfoundation.org, colin.i.king@gmail.com,
xuetao09@huawei.com, quic_eserrao@quicinc.com,
water.zhangjiantao@huawei.com, peter.chen@freescale.com,
balbi@ti.com, francesco@dolcini.it, alistair@alistair23.me,
stephan@gerhold.net, bagasdotme@gmail.com, luca@z3ntu.xyz,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org,
Francesco Dolcini <francesco.dolcini@toradex.com>
Subject: Re: [PATCH v2] usb: gadget: udc: core: Offload usb_udc_vbus_handler processing
Date: Fri, 19 May 2023 10:49:49 -0400 [thread overview]
Message-ID: <c181c8ef-f342-4a31-9b8c-e1fa14ad214e@rowland.harvard.edu> (raw)
In-Reply-To: <20230519043041.1593578-1-badhri@google.com>
On Fri, May 19, 2023 at 04:30:41AM +0000, Badhri Jagan Sridharan wrote:
> chipidea udc calls usb_udc_vbus_handler from udc_start gadget
> ops causing a deadlock. Avoid this by offloading usb_udc_vbus_handler
> processing.
Look, this is way overkill.
usb_udc_vbus_handler() has only two jobs to do: set udc->vbus and call
usb_udc_connect_control(). Furthermore, it gets called from only two
drivers: chipidea and max3420.
Why not have the callers set udc->vbus themselves and then call
usb_gadget_{dis}connect() directly? Then we could eliminate
usb_udc_vbus_handler() entirely. And the unnecessary calls -- the ones
causing deadlocks -- from within udc_start() and udc_stop() handlers can
be removed with no further consequence.
This approach simplifies and removes code. Whereas your approach
complicates and adds code for no good reason.
Alan Stern
next prev parent reply other threads:[~2023-05-19 14:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-19 4:30 [PATCH v2] usb: gadget: udc: core: Offload usb_udc_vbus_handler processing Badhri Jagan Sridharan
2023-05-19 14:49 ` Alan Stern [this message]
2023-05-19 15:07 ` Alan Stern
2023-05-19 15:44 ` Badhri Jagan Sridharan
2023-05-19 17:27 ` Alan Stern
2023-05-22 7:48 ` Badhri Jagan Sridharan
2023-05-22 9:05 ` Badhri Jagan Sridharan
2023-05-22 15:55 ` Alan Stern
2023-05-27 2:42 ` Badhri Jagan Sridharan
2023-05-27 16:36 ` Alan Stern
2023-05-29 23:32 ` Badhri Jagan Sridharan
2023-05-30 0:42 ` Alan Stern
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