Subject: Re: [PATCH] b43: Replace mdelay with msleep in
 b43_radio_2057_init_post
To: Jia-Ju Bai <baijiaju1990@gmail.com>, kvalo@codeaurora.org,
        colin.king@canonical.com, johannes.berg@intel.com, tiwai@suse.de,
        kstewart@linuxfoundation.org, gregkh@linuxfoundation.org,
        andrew.zaborowski@intel.com
Cc: linux-wireless@vger.kernel.org, b43-dev@lists.infradead.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1514632107-14698-1-git-send-email-baijiaju1990@gmail.com>
From: Larry Finger <Larry.Finger@lwfinger.net>
Message-ID: <906de5ba-b572-ada0-68ad-5e161ef6016e@lwfinger.net> (sfid-20171230_195020_091831_79CCB058)
Date: Sat, 30 Dec 2017 12:49:50 -0600
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In-Reply-To: <1514632107-14698-1-git-send-email-baijiaju1990@gmail.com>
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Sender: linux-wireless-owner@vger.kernel.org

On 12/30/2017 05:08 AM, Jia-Ju Bai wrote:
> b43_radio_2057_init_post is not called in an interrupt handler
> nor holding a spinlock.
> The function mdelay in it can be replaced with msleep, to reduce busy wait.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>

checkpatch.pl reports the following warning for this patch:

WARNING: msleep < 20ms can sleep for up to 20ms; see 
Documentation/timers/timers-howto.txt
#26: FILE: drivers/net/wireless/broadcom/b43/phy_n.c:1034:
+       msleep(2);

total: 0 errors, 1 warnings, 0 checks, 8 lines checked

Have you tested to verify that a sleep as long as 20 ms will not cause problems? 
The referenced document suggests a usleep_range() call.

In general, delay changes should never be proposed without testing.

Larry