Messages in this thread | | | Date | Mon, 16 Jun 2014 11:37:22 -0400 | From | Peter Hurley <> | Subject | Re: Linux 3.15: SPARC serial console regression |
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On 06/15/2014 02:56 PM, Sam Ravnborg wrote: > Hi Peter. > > On Tue, Jun 10, 2014 at 05:20:08PM -0400, Peter Hurley wrote: >> Hi Sam, >> >> On 06/10/2014 03:24 PM, Sam Ravnborg wrote: >>>> From: Peter Hurley <peter@hurleysoftware.com> >>>> Date: Mon, 9 Jun 2014 19:21:43 -0400 >>>> Subject: [PATCH] serial: sunsab: Test for no tx data on tx restart >>>> >>>> Commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c, >>>> 'serial_core: Fix conditional start_tx on ring buffer not empty' >>>> exposes an incorrect assumption in sunsab's start_tx method; the >>>> tx ring buffer can, in fact, be empty when restarting tx when >>>> performing flow control. > > We have a report that commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c > ("serial_core: Fix conditional start_tx on ring buffer not empty") > broke at least one more driver: > > Aaro Koskinen <aaro.koskinen@iki.fi> reported: > The same problem is present also on PowerPC G5 Xserve (pmac_zilog driver) > > And based on code review a third driver is broken: > > Sam Ravnborg <sam@ravnborg.org> reported: > Can you please take a look at sunzilog.c. > It looks like the same test is missing in sunzilog_start_tx(): > > This is a regression so we should either revert the above commit > or review and fix the remaining drivers.
I'm working on the audit right now, but its not entirely accurate to call this is a regression.
All of these drivers were already broken on resume-from-suspend and hard flow control restart.
Regards, Peter Hurley
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