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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Jeaho Hwang <jhhwang@rtst.co.kr>
Cc: "Peter Chen" <peter.chen@kernel.org>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Thomas Gleixner" <tglx@linutronix.de>,
	linux-rt-users@vger.kernel.org,
	"Linux team" <team-linux@rtst.co.kr>,
	"변무광(Byeon Moo Kwang)/자동화연)Automation Platform연구팀"
	<mkbyeon@lselectric.co.kr>,
	"최기홍(Choi Ki Hong)/자동화연)Automation Platform연구팀"
	<khchoib@lselectric.co.kr>
Subject: Re: [PATCH v2] usb: chipidea: local_irq_save/restore added for hw_ep_prime
Date: Mon, 23 Aug 2021 18:51:02 +0200	[thread overview]
Message-ID: <20210823165102.gk5ibzgi6qlgvrxf@linutronix.de> (raw)
In-Reply-To: <CAJk_X9gyWch6Z1=hbe2vvqGu61mdavAU62+6dSka0tZoMzxu5Q@mail.gmail.com>

On 2021-08-20 14:15:55 [+0900], Jeaho Hwang wrote:
> So we protect irqs inside hw_ep_priming not to make error cases and
> also add a timeout inside the hw_ep_set_halt loop for a walkaround.
> The timeout patch is submitted to linux-usb.
> ( https://marc.info/?l=linux-usb&m=162918269024007&w=2 )
>
> We withdrew this patch since we don't know if disabling irq is the
> best solution to solve the problem and udc would work fine with
> hw_ep_set_halt walkaround even though hw_ep_prime fails.
> But we are still trying to find out the cause of this symptom so We'd
> so appreciate it if RT or USB experts share some ideas or ways to
> report somewhere. Xilinx doesn't provide any support without their
> official kernel :(

The UDC driver sometimes drops the lock and acquires it again. On UP it
would not matter but on SMP/RT the other may acquire lock and do
something with the HW. One thing that you could check if there is any HW
access in between which would affect the behaviour.

> Thanks for the discussion Sebastian.
> 
> Jeaho Hwang.

Sebastian

      parent reply	other threads:[~2021-08-23 16:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-17  9:53 Jeaho Hwang
2021-08-18 16:17 ` Sebastian Andrzej Siewior
2021-08-18 23:50   ` Jeaho Hwang
2021-08-19  8:47     ` Sebastian Andrzej Siewior
2021-08-20  5:15       ` Jeaho Hwang
2021-08-21  5:05         ` Peter Chen
2021-08-21  7:04           ` Jeaho Hwang
2021-08-23 16:14             ` Sebastian Andrzej Siewior
2021-08-23 16:51         ` Sebastian Andrzej Siewior [this message]

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