lkml.org 
[lkml]   [2020]   [May]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v4 01/16] spi: dw: Add Tx/Rx finish wait methods to the MID DMA
On Fri, May 22, 2020 at 01:18:20PM +0100, Mark Brown wrote:
> On Fri, May 22, 2020 at 03:12:21PM +0300, Andy Shevchenko wrote:
> > On Fri, May 22, 2020 at 02:52:35PM +0300, Serge Semin wrote:
>
> > > Please, see it's implementation. It does atomic delay when the delay value
> > > is less than 10us. But selectively gets to the usleep_range() if value is
> > > greater than that.
>
> > Oh, than it means we may do a very long busy loop here which is not good at
> > all. If we have 10Hz clock, it might take seconds of doing nothing!
>
> Realistically it seems unlikely that the clock will be even as slow as
> double digit kHz though, and if we do I'd not be surprised to see other
> problems kicking in. It's definitely good to handle such things if we
> can but so long as everything is OK for realistic use cases I'm not sure
> it should be a blocker.

Perhaps some kind of warning? Funny that using spi_delay_exec() will issue such
a warning as a side effect of its implementation.

--
With Best Regards,
Andy Shevchenko


\
 
 \ /
  Last update: 2020-05-22 14:34    [W:0.091 / U:1.788 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site