From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Hurley Date: Fri, 06 Dec 2013 15:54:24 +0000 Subject: Re: RED state exception (trap type 0x64) on U5 reboot Message-Id: <52A1F330.5020800@hurleysoftware.com> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: sparclinux@vger.kernel.org On 12/04/2013 10:35 AM, Meelis Roos wrote: >>>>>> There were some changes to sunsab.c a couple of versions ago; maybe we >>>>>> broke it. >>>>>> >>>>>> Can you confirm BRKs are being received with >>>>>> 'sudo cat /proc/tty/driver/serial' >>>>> >>>>> In 3.12: >>>>> >>>>> # cat /proc/tty/driver/sunsab >>>>> serinfo:1.0 driver revision: >>>>> 0: uart:SAB82532 V3.2 mmio:0x1FFF1400000 irq:5 tx:5163 rx:0 CTS|DSR|CD >>>>> 1: uart:SAB82532 V3.2 mmio:0x1FFF1400040 irq:5 tx:0 rx: >>>>> >>>>> cat /proc/sys/kernel/stop-a >>>>> 1 >>>>> >>>>> # cat /proc/sys/kernel/reboot-cmd >>>>> >>>>> (it was empty, so default "boot" should be used AFAIK) >>>> >>>> Meelis, >>>> >>>> Would you please re-test trying to break to the PROM with this debug >>>> patch? As with the bootpromfs debug patch, the output is in >>>> '/sys/kernel/debug/trace'. >>> >>> Should I activate tracing somehow? >> >> You did activate tracing. The lack of output means at that point >> there is no BRK detected. Can you trigger any sysrq function from >> that terminal (assuming CONFIG_SERIAL_SUNSAB_CONSOLE && CONFIG_MAGIC_SYSRQ)? > > I can not trigger SysRq by sending a break and then immediately s (or t > also tested). Nothing in trace. Magic SysRq is 0x1 like default in > kernel conf. This in on the SUNSAB Ultra5 machine. That's what I thought: just wanted to validate. Not sure why no BRK is detected (isr1 & ISR1_BRK = 0). Maybe there is an early-out that is ignoring BRK condition. Or the sunsab driver is not reading/interpreting the correct register/bits. You could instrument the irq handler, sunsab_interrupt(), with trace_printk() to see if BRK is ever detected. > E3500 with zs serial console has working break but I do now know how to > send SysRq there - Break drops me to prom prompt, I can "go" there but > anything after that is inteprreted as normal input. I'm not sure how BRK is intended to be used for both the PROM console and SysRq on a serial console. If you temporarily disable the PROM console, the SysRq should work by typing a SysRq command char after sending a break. [ FWIW, Minicom's break function sends a lot of BRKs because it's designed to trigger a modem interrupt. AFAIK there isn't a 'single-char length break' supported by minicom. ] > How shoyukd SysRq > over verial console work - have not used it before? The first input after a BRK is interpreted as a SysRq command (within 5 secs). Regards, Peter Hurley