Hi Shawn,
On 09/01/2014 07:28, Shawn Guo wrote:
On Thu, Jan 09, 2014 at 03:50:06AM +0000, Hui.Liu@freescale.com wrote:
The commit log really get me confused, why we need enable one ERRATA which should not be applied?
It's been enabled as a workaround for the reboot issue we were seeing before. But I get reminded that the workaround may not be needed anymore, because of the recent kernel commit 87a84b69 (ARM: imx: replace imx6q_restart() with mxc_restart()). The real change is that we do not call of_iomap() in restart hook now.
Fabio,
Can you give it a test to see if reboot works fine with v3.13-rc kernel with dropping the ERRATA from u-boot? If reboot works and nothing else breaks, we may want to just remove the ERRATA selection from u-boot.
+1
If the workaround must be set for dual/quad, it is not clear to me if there are some disadvantages to let it enabled for solo.
This will make customer confused at all. We need find the real root-cause for it other than hack it Otherwise, you will get more and more problems sooner or later...
If you go through the thread [1], you will see that the root-cause had pretty much been identified, - issuing dmb instructions in a tight loop causes the problem. But people did not reach a conclusion how it should be fixed.
Exactly, and more frightening IMHO is what can happen is user space if gcc uses dmb.
Regards, Stefano