Re: [PATCH] add delay between port write and port read

From: Mikulas Patocka (mpatocka@xxxxxxxxxx)
Date: Wed Feb 27 2019 - 12:12:53 EST




On Tue, 26 Feb 2019, Linus Torvalds wrote:

> Does anybody see any worries with the "just move the mb() earlier in
> the ioread functions" model?
>
> Linus

It used to be like that and it worked.

Then, commits cd0e00c106722eca40b38ebf11cf134c01901086 and
92d7223a74235054f2aa7227d207d9c57f84dca0 came.

These commits claim that they changed the code to be consistent with the
specification (now we have barrier after ioread and before iowrite). But
they broke serial port and RTC on my Alpha machine.

Mikulas