From: Fabio Estevam <festevam@xxxxxxxxx> Sent: Tuesday, October 28, 2014 7:28 PM
>To: Duan Fugang-B38611
>Cc: Estevam Fabio-R49496; gregkh@xxxxxxxxxxxxxxxxxxx; shawn.guo@xxxxxxxxxx;
>kernel@xxxxxxxxxxxxxx; linux-serial@xxxxxxxxxxxxxxx
>Subject: Re: [PATCH 1/4] serial: imx: Fix the reporting of interrupts
>
>Hi Andy,
>
>On Tue, Oct 28, 2014 at 12:10 AM, fugang.duan@xxxxxxxxxxxxx
><fugang.duan@xxxxxxxxxxxxx> wrote:
>
>> Hi, Fabio,
>>
>> After the patch, uart wake up feature may be break. (So I always don't
>> do like this.)
>>
>> Since the current driver enable AWAKE before system suspend in
>> default, after suspend, if user click console keys, it generates AWAKE
>interrupt, in the irq handler, there have register access that cause
>system hang since uart module/ipg clocks are disabled, and system cannot
>resume back.
>
>I have tested suspend/resume on a mx6qsabresd with this patch applied:
>
>root@freescale /$ echo enabled > /sys/class/tty/ttymxc0/power/wakeup
>root@freescale /$ echo mem > /sys/power/state
>[ 61.322648] PM: Syncing filesystems ... done.
>[ 61.342263] Freezing user space processes ... (elapsed 0.001 seconds)
>done.
>[ 61.351159] Freezing remaining freezable tasks ... (elapsed 0.002
>seconds) d.
>[ 61.360875] Suspending console(s) (use no_console_suspend to debug)
>
>(then sent a char in console)
>
>[ 61.416329] PM: suspend of devices complete after 45.778 msecs
>[ 61.416337] PM: suspend devices took 0.050 seconds
>[ 61.420745] PM: late suspend of devices complete after 4.393 msecs
>[ 61.425547] PM: noirq suspend of devices complete after 4.787 msecs
>[ 61.425555] Disabling non-boot CPUs ...
>[ 61.426971] CPU1: shutdown
>[ 61.429095] CPU2: shutdown
>[ 61.431190] CPU3: shutdown
>[ 61.431992] Enabling non-boot CPUs ...
>[ 61.432635] CPU1: Booted secondary processor
>[ 61.433006] CPU1 is up
>[ 61.433627] CPU2: Booted secondary processor
>[ 61.433998] CPU2 is up
>[ 61.434622] CPU3: Booted secondary processor
>[ 61.435021] CPU3 is up
>[ 61.437511] PM: noirq resume of devices complete after 2.472 msecs
>[ 61.441288] PM: early resume of devices complete after 2.909 msecs
>[ 61.602251] PM: resume of devices complete after 160.946 msecs
>[ 61.606860] PM: resume devices took 0.170 seconds
>[ 61.688676] Restarting tasks ... done.
>[ 61.795155] ata1: SATA link down (SStatus 0 SControl 300)
>
>and the system wakes up normally.
Ok, if wake up function still work, the patch is fine for me.
But I suggest you do one test like this:
1. echo enabled > /sys/class/tty/ttymxc0/power/wakeup
2. echo mem > /sys/power/state
3. ..quickly click console key in continuously.
(Make sure the delay between step2 and step3 is little)
Regards,
Andy
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