From: Roger Quadros <rogerq@ti.com>
To: David Laight <David.Laight@ACULAB.COM>,
lee.jones@linaro.org, sameo@linux.intel.com
Cc: tomi.valkeinen@ti.com, balbi@ti.com, sr@denx.de,
ljkenny.mailinglists@gmail.com, linux-omap@vger.kernel.org,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] mfd: omap-usb-host: Fix USB device detection problems on OMAP4 Panda
Date: Tue, 3 Dec 2013 11:43:18 +0200 [thread overview]
Message-ID: <529DA7B6.4020402@ti.com> (raw)
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6026B7455@saturn3.aculab.com>
On 12/02/2013 06:28 PM, David Laight wrote:
>> From: Roger Quadros [mailto:rogerq@ti.com]
>> On 11/29/2013 03:17 PM, David Laight wrote:
> ...
>>>> + timeout = jiffies + msecs_to_jiffies(100);
>>>> + while (!(usbhs_read(omap->uhh_base, OMAP_UHH_SYSSTATUS)
>>>> + & OMAP_UHH_SYSSTATUS_RESETDONE)) {
>>>> + cpu_relax();
>>
>> You mean use msleep(1) here instead of cpu_relax()?
>> Shouldn't be a problem IMO, but can you please tell me why that is better
>> as the reset seems to complete usually in the first iteration.
>
> If it doesn't finish in the first iteration you don't want to
> spin the cpu for 100ms.
>
> If it hasn't finished in the first millisecond, you probably expect
> it to actually time out - so you might as well look (say) every 10ms.
>
Understood now. Thanks.
cheers,
-roger
WARNING: multiple messages have this Message-ID (diff)
From: Roger Quadros <rogerq@ti.com>
To: David Laight <David.Laight@ACULAB.COM>, <lee.jones@linaro.org>,
<sameo@linux.intel.com>
Cc: <tomi.valkeinen@ti.com>, <balbi@ti.com>, <sr@denx.de>,
<ljkenny.mailinglists@gmail.com>, <linux-omap@vger.kernel.org>,
<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/1] mfd: omap-usb-host: Fix USB device detection problems on OMAP4 Panda
Date: Tue, 3 Dec 2013 11:43:18 +0200 [thread overview]
Message-ID: <529DA7B6.4020402@ti.com> (raw)
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6026B7455@saturn3.aculab.com>
On 12/02/2013 06:28 PM, David Laight wrote:
>> From: Roger Quadros [mailto:rogerq@ti.com]
>> On 11/29/2013 03:17 PM, David Laight wrote:
> ...
>>>> + timeout = jiffies + msecs_to_jiffies(100);
>>>> + while (!(usbhs_read(omap->uhh_base, OMAP_UHH_SYSSTATUS)
>>>> + & OMAP_UHH_SYSSTATUS_RESETDONE)) {
>>>> + cpu_relax();
>>
>> You mean use msleep(1) here instead of cpu_relax()?
>> Shouldn't be a problem IMO, but can you please tell me why that is better
>> as the reset seems to complete usually in the first iteration.
>
> If it doesn't finish in the first iteration you don't want to
> spin the cpu for 100ms.
>
> If it hasn't finished in the first millisecond, you probably expect
> it to actually time out - so you might as well look (say) every 10ms.
>
Understood now. Thanks.
cheers,
-roger
next prev parent reply other threads:[~2013-12-03 9:43 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-29 13:01 [PATCH 0/1] mfd: omap-usb-host: Bug fix for 3.13 rc Roger Quadros
2013-11-29 13:01 ` Roger Quadros
2013-11-29 13:01 ` [PATCH 1/1] mfd: omap-usb-host: Fix USB device detection problems on OMAP4 Panda Roger Quadros
2013-11-29 13:01 ` Roger Quadros
2013-11-29 13:17 ` David Laight
2013-11-29 13:17 ` David Laight
2013-12-02 8:39 ` Roger Quadros
2013-12-02 8:39 ` Roger Quadros
2013-12-02 16:28 ` David Laight
2013-12-02 16:28 ` David Laight
2013-12-03 9:43 ` Roger Quadros [this message]
2013-12-03 9:43 ` Roger Quadros
[not found] ` <1385730118-26402-2-git-send-email-rogerq-l0cyMroinI0@public.gmane.org>
2013-11-29 15:32 ` Michael Trimarchi
2013-11-29 15:32 ` Michael Trimarchi
2013-12-02 9:41 ` Roger Quadros
2013-12-02 9:41 ` Roger Quadros
2013-12-02 12:01 ` Sebastian Andrzej Siewior
2013-12-02 12:12 ` Roger Quadros
2013-12-02 12:12 ` Roger Quadros
2013-12-02 13:04 ` Sebastian Andrzej Siewior
2013-12-02 13:35 ` Roger Quadros
2013-12-02 13:35 ` Roger Quadros
2013-12-02 13:39 ` Sebastian Andrzej Siewior
2013-12-02 13:44 ` Roger Quadros
2013-12-02 13:44 ` Roger Quadros
[not found] ` <529C8ED0.6060805-l0cyMroinI0@public.gmane.org>
2013-12-02 14:03 ` Sebastian Andrzej Siewior
2013-12-02 14:03 ` Sebastian Andrzej Siewior
2013-12-02 15:12 ` Roger Quadros
2013-12-02 15:12 ` Roger Quadros
2013-11-30 4:48 ` Michael Trimarchi
2013-11-30 5:10 ` Michael Trimarchi
2013-12-01 3:14 ` Michael Trimarchi
2013-12-02 9:39 ` Roger Quadros
2013-12-02 9:39 ` Roger Quadros
2013-12-02 9:51 ` Michael Trimarchi
[not found] ` <CAOf5uwmpiOv_GED23hWDArcOvs6DpHNEy=OJ9vnKem1pg8jSgw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-12-02 12:05 ` Roger Quadros
2013-12-02 12:05 ` Roger Quadros
2013-12-02 15:00 ` Paul Walmsley
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