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Subject: Re: [PATCH] rtlwifi: Fix scheduling while atomic error from commit
 49f86ec21c01
To: Kalle Valo <kvalo@codeaurora.org>
References: <1463849435-2293-1-git-send-email-Larry.Finger@lwfinger.net>
 <878tz2bpv0.fsf@kamboji.qca.qualcomm.com>
Cc: devel@driverdev.osuosl.org, linux-wireless@vger.kernel.org,
	James Feeney <james@nurealm.net>
From: Larry Finger <Larry.Finger@lwfinger.net>
Message-ID: <5741C64D.8050603@lwfinger.net> (sfid-20160522_165851_292220_EC756B9A)
Date: Sun, 22 May 2016 09:46:37 -0500
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On 05/22/2016 12:53 AM, Kalle Valo wrote:
> Larry Finger <Larry.Finger@lwfinger.net> writes:
>
>> Commit 49f86ec21c01 ("rtlwifi: Change long delays to sleeps") was correct
>> for most cases; however, driver rtl8192ce calls the affected routines while
>> in atomic context. The kernel bug output is as follows:
>>
>> BUG: scheduling while atomic: wpa_supplicant/627/0x00000002
>> [...]
>>    [<ffffffff815c2b39>] __schedule+0x899/0xad0
>>    [<ffffffff815c2dac>] schedule+0x3c/0x90
>>    [<ffffffff815c5bb2>] schedule_hrtimeout_range_clock+0xa2/0x120
>>    [<ffffffff810e8b80>] ? hrtimer_init+0x120/0x120
>>    [<ffffffff815c5ba6>] ? schedule_hrtimeout_range_clock+0x96/0x120
>>    [<ffffffff815c5c43>] schedule_hrtimeout_range+0x13/0x20
>>    [<ffffffff815c568f>] usleep_range+0x4f/0x70
>>    [<ffffffffa0667218>] rtl_rfreg_delay+0x38/0x50 [rtlwifi]
>>    [<ffffffffa06dd0e7>] rtl92c_phy_config_rf_with_headerfile+0xc7/0xe0 [rtl8192ce]
>>
>> To fix this bug, three of the changes from delay to sleep are reverted.
>> Unfortunately, one of the changes involves a delay of 50 msec. The calling
>> code will be modified so that this long delay can be avoided; however,
>> this change is being pushed now to fix the problem in kernel 4.6.0.
>>
>> Fixes: 49f86ec21c01 ("rtlwifi: Change long delays to sleeps")
>> Reported-by: James Feeney <james@nurealm.net>
>> Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
>> Cc: James Feeney <james@nurealm.net>
>> Cc: Stable <stable@vger.kernel.org> [4.6+]
>
> I'm planning to queue this to 4.7.

That will be good as it will be ported to 4.6 quickly after that.

Larry