From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750788AbWHKLI1 (ORCPT ); Fri, 11 Aug 2006 07:08:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932100AbWHKLI1 (ORCPT ); Fri, 11 Aug 2006 07:08:27 -0400 Received: from mail.oxtel.com ([195.219.3.158]:26118 "EHLO oxtel.com") by vger.kernel.org with ESMTP id S1750973AbWHKLI0 (ORCPT ); Fri, 11 Aug 2006 07:08:26 -0400 Message-ID: <44DC6524.4000401@miranda.com> Date: Fri, 11 Aug 2006 12:08:20 +0100 From: Chris Pringle User-Agent: Thunderbird 1.5.0.5 (Windows/20060719) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: Serial driver 8250 hangs the kernel with the VIA Nehemiah... Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated-Sender: chris.pringle X-Server: VPOP3 Enterprise V2.3.0e - Registered Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: > Ar Gwe, 2006-08-11 am 09:52 +0100, ysgrifennodd Chris Pringle: > >> on it. However, when the port is receiving a lot of data, it has the >> tendency to either get corrupted data, or to crash the kernel. >> > > What do the crash traces look like > Sorry - the kernel hangs, not crashes. There is no output whatsoever after the hang - SysRq doesn't work, but Numlock does. > >> The "inb" as it is will sometimes return bad data - I'm guessing this >> is due to ISA bus instability... Anyway I changed it to "inb_p" which >> cured the corruption problem, but has introduced another issue - it >> hangs the kernel. >> > > Maybe you need to have a chat with your hardware guys. Certainly if > inb_p makes a difference you've got hardware not software side problems. > Perhaps - I'm in discussion with them at the moment, but neither our, nor their department have managed to come up with an answer yet. > >> Interestingly, it only hangs on systems with a VIA Nehemiah CPU, the >> Intel Celerons seem to work fine. Could this be a problem with writing >> to that dreaded port 0x080 within inb_p? >> > > Unlikely as it would affect both. More likely would be that the ISA bus > clock is generated off the PCI bus clock and you have one of the > multipliers wrong or too high for the board. > Thats interesting, but wouldn't this produce strange side affects for the 2.4 kernel as well? 2.4 works fine on both VIAs and Celerons. > >> it only occur on the VIA chip and not the Celeron? I don't think the >> problem is there when the low latency patches are not applied - so I'm >> thinking it's probably a timing problem of some sort. >> > > That bit is interesting. Something really off the wall to try - disable > interrupts around the inb_p(), especially if you are using pre-emption > and let me know what happens. > > Alan > > - > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > I'll give the interrupt disabling a go... Thanks Alan. Chris. -- ______________________________ Chris Pringle Software Engineer Miranda Technologies Ltd. Hithercroft Road Wallingford Oxfordshire OX10 9DG UK Tel. +44 1491 820206 Fax. +44 1491 820001 www.miranda.com