[RFC/RFT PATCH 2/2] SERIAL: OMAP: Remove the idle handling from the driver
santosh.shilimkar at ti.com
Fri Feb 15 08:43:42 EST 2013
On Friday 15 February 2013 07:04 PM, Felipe Balbi wrote:
> On Fri, Feb 15, 2013 at 06:49:20PM +0530, Santosh Shilimkar wrote:
>>>> @@ -279,8 +259,6 @@ static void serial_omap_stop_tx(struct uart_port *port)
>>>> serial_out(up, UART_IER, up->ier);
>>>> - serial_omap_set_forceidle(up);
>>>> @@ -348,7 +326,6 @@ static void serial_omap_start_tx(struct uart_port *port)
>>>> - serial_omap_set_noidle(up);
>>> this patch is changing behavior. Currently driver has:
>>> with this change, you will have:
>>> this in itself might be enough to go back to corrupted serial if
>>> put_autosuspend is so quick that set_force_idle() is called before all
>>> data has been shifted out of FIFO and through the UART lines.
>> Really. Infact the old sequence was buggy because you are setting
>> force_idle even before suspending the device. And that force idle
> then that bug has to be fixed first and patch needs to be sent to stable
> before we change that part of the code, wouldn't you agree ?
Agree. Will be good to get that fixed for stable. Probably Sourabh
can fix that one.
>> isn't really force idle but setting ip to smart idle. Just look at
>> what serial.c
>>> Before doing this, you should at least test that removing
>>> pm_runtime_mark_last_busy() and pm_runtime_put_autosuspend() from
>>> start_tx() and removing pm_runtime_get_sync() from stop_tx() works fine.
>> Seems to work for me with above changes as well. Can you please
>> try out and see if you see any issue. I doubt you will...
> what I'm saying is that current code, as you put it yourself, is buggy,
> so we ought to fix the bugs first before changing behavior. If not for
> anything else, at least to have a clean tree which we can bisect.
>>> Also, $SUBJECT isn't improving the situation regarding UART Wakeup,
>>> there is still the regression of UART never being wakeup capable.
>> You are mixing the stuff here. The subject is correct.
> ->enable_wakeup() sets the IP to smart_idle_wakeup, which is done on
> SYSC register. If $SUBJECT wants to fix SYSC usage, it ought to fix them
But SYSC is already in smart_idle_wakeup() mode. I get your point
though. The main purpose of that wakeup hook is to trigger io_ring
and pad wakeup.
BTW, Rajendra is looking at how to get rid of wakeup function pointer
as well since that also comes in way for DT.
More information about the linux-arm-kernel