Messages in this thread | | | Date | Wed, 10 Jun 2020 17:01:24 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH 4.19 15/28] spi: dw: use "smp_mb()" to avoid sending spi data error |
| |
On Mon 2020-06-08 12:16:19, Mark Brown wrote: > On Sun, Jun 07, 2020 at 10:09:11PM +0200, Pavel Machek wrote: > > > > Because of out-of-order execution about some CPU architecture, > > > In this debug stage we find Completing spi interrupt enable -> > > > prodrucing TXEI interrupt -> running "interrupt_transfer" function > > > will prior to set "dw->rx and dws->rx_end" data, so this patch add > > > memory barrier to enable dw->rx and dw->rx_end to be visible and > > > solve to send SPI data error. > > > So, this is apparently CPU-vs-device issue... > > The commit message is a bit unclear but my read had been interrupt > handler racing with sending new data rather than an ordering issue with > writes to the hardware.
Aha, patch makes sense, then. Thanks for explanation! Pavel -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany [unhandled content-type:application/pgp-signature] | |