From: Peter Zijlstra <peterz@infradead.org>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mathias Nyman <mathias.nyman@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
tglx@linutronix.de, linux-usb@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, Jiri Slaby <jslaby@suse.cz>
Subject: Re: [PATCH v5 1/4] usb: dbc: early driver for xhci debug capability
Date: Wed, 25 Jan 2017 15:38:29 +0100 [thread overview]
Message-ID: <20170125143829.GS6515@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <588899BA.7040108@linux.intel.com>
On Wed, Jan 25, 2017 at 08:27:38PM +0800, Lu Baolu wrote:
> In my driver, udelay() is mostly used to handle time out.
>
> Xdbc hides most USB things in its firmware. Early printk driver only needs
> to setup the registers/data structures and wait until link ready or time out.
> Without udelay(), I have no means to convert the polling times into waiting
> time.
What is timeout and why? If there is an error other than !ready, I would
expect the hardware to inform you of this through another status bit,
no?
So why can't you poll indefinitely for either ready or error?
next prev parent reply other threads:[~2017-01-25 14:38 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-15 6:02 [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port Lu Baolu
2016-11-15 6:02 ` [PATCH v5 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu
2017-01-19 9:37 ` Ingo Molnar
2017-01-20 2:47 ` Lu Baolu
2017-01-22 9:04 ` Ingo Molnar
2017-01-24 4:44 ` Lu Baolu
2017-01-24 8:20 ` Ingo Molnar
2017-01-25 5:28 ` Lu Baolu
2017-01-25 9:23 ` Ingo Molnar
2017-01-25 9:57 ` Peter Zijlstra
2017-01-25 12:27 ` Lu Baolu
2017-01-25 14:38 ` Peter Zijlstra [this message]
2017-01-25 15:51 ` Lu Baolu
2017-01-25 16:16 ` Peter Zijlstra
2017-01-26 3:37 ` Lu Baolu
2017-01-26 7:19 ` Ingo Molnar
2017-01-26 7:49 ` Lu Baolu
2017-01-26 8:17 ` Ingo Molnar
2017-01-26 10:28 ` Peter Zijlstra
2017-01-26 16:01 ` Ingo Molnar
2017-01-26 17:39 ` Peter Zijlstra
2017-01-27 6:51 ` Ingo Molnar
2017-02-09 5:59 ` Lu Baolu
2017-01-26 7:22 ` Ingo Molnar
2017-02-09 7:37 ` Lu Baolu
2017-01-25 12:17 ` Lu Baolu
2017-01-26 3:26 ` Lu Baolu
2016-11-15 6:02 ` [PATCH v5 2/4] x86: add support for earlyprintk via USB3 debug port Lu Baolu
2017-01-19 9:38 ` Ingo Molnar
2017-01-20 2:48 ` Lu Baolu
2016-11-15 6:02 ` [PATCH v5 3/4] usb: serial: usb_debug: add support for dbc debug device Lu Baolu
2017-01-19 9:39 ` Ingo Molnar
2017-01-20 2:50 ` Lu Baolu
2016-11-15 6:02 ` [PATCH v5 4/4] usb: doc: add document for USB3 debug port usage Lu Baolu
2017-01-19 9:41 ` Ingo Molnar
2017-01-20 2:53 ` Lu Baolu
2017-01-18 6:20 ` [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port Lu Baolu
2017-01-19 9:06 ` Greg Kroah-Hartman
2017-01-19 9:09 ` Ingo Molnar
2017-01-19 11:24 ` Mathias Nyman
2017-01-19 9:12 ` Ingo Molnar
2017-01-20 2:56 ` Lu Baolu
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