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Date: Wed, 11 Nov 2015 13:29:59 +0100 From: Mirza Krak <mirza.krak@...tmobility.com> To: Marc Kleine-Budde <mkl@...gutronix.de> Cc: wg@...ndegger.com, andri.yngvason@...el.com, "linux-can@...r.kernel.org" <linux-can@...r.kernel.org>, netdev@...r.kernel.org, linux-kernel <linux-kernel@...r.kernel.org>, Christian Magnusson <Christian.Magnusson@...con.com> Subject: Re: [PATCH 1/1] can: sja1000: clear interrupts on start 2015-11-11 11:06 GMT+01:00 Marc Kleine-Budde <mkl@...gutronix.de>: > On 11/11/2015 10:54 AM, Mirza Krak wrote: >> 2015-11-11 9:04 GMT+01:00 Marc Kleine-Budde <mkl@...gutronix.de>: >>> This problem occurs only an hardware, where the SJA1000 is powered >>> during system suspend? >> >> Correct, and the controller is in UP state. >> >>> Doesn't the SJA1000 trigger an interrupt that is detected after >>> resuming? You add the fix to the open() function, which is triggered >>> during $(ifconfig up), how is related to suspend/resume? Does the >>> network layer call $(ifconfig down) during shutdown? >> >> It does not trigger another interrupt. > > Can you put a scope on the interrupt pin and see if it's a problem of > the SoC and/or Linux or the SJA1000 not pulling the IRQ line. A little demonstration on what it looks like when the system is resumed (added a printk in sja1000_start without my patch, though my printk also clears IR register): root@...-vcc:/opt/hm# ip -det link show can0 33: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN mode DEFAULT qlen 10 link/can can state ERROR-ACTIVE (berr-counter tx 0 rx 128) restart-ms 0 bitrate 500000 sample-point 0.875 tq 250 prop-seg 3 phase-seg1 3 phase-seg2 1 sjw 1 sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 clock 12000000 root@...-vcc:/opt/hm# ifconfig can0 down root@...-vcc:/opt/hm# ifconfig can0 up [ 1612.621187] sja1000: MOD: 0x1 [ 1612.640992] sja1000: SR: 0x7c [ 1612.660039] sja1000: IR: 0x24 Also did a measurement with the scope, it is the SJA1000 chip not pulling the IRQ line. I can actually send one frame when the controller is in this state but never get a TI interrupt. root@...-vcc-14381059:~/test/can_test# ip -det link show can0 17: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN mode DEFAULT qlen 10 link/can can state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0 bitrate 125000 sample-point 0.875 tq 500 prop-seg 6 phase-seg1 7 phase-seg2 2 sjw 1 sja1000: tseg1 1..16 tseg2 1..8 sjw 1..4 brp 1..64 brp-inc 1 clock 12000000 root@...-vcc-14381059:~/test/can_test# cansend can0 -i 123 0 1 2 interface = can0, family = 29, type = 3, proto = 1 root@...-vcc-14381059:~/test/can_test# cansend can0 -i 123 0 1 2 interface = can0, family = 29, type = 3, proto = 1 root@...-vcc-14381059:~/test/can_test# cansend can0 -i 123 0 1 2 interface = can0, family = 29, type = 3, proto = 1 root@...-vcc-14381059:~/test/can_test# cat /proc/interrupts | grep can0 205: 0 0 GPIO can0 root@...-vcc-14381059:~/test/can_test# ## Second unit root@...-t20-1000000:~/test/can_test# candump can0 interface = can0, family = 29, type = 3, proto = 1 <0x07b> [3] 00 01 02 >>> There isn't any suspend/resume code in the sja1000 driver, for me it >>> seems that we should add resume code that handles this problem. >> >> Yes, resume code should be implemented to handle this and other >> problems (receive data). But still a DOWN/UP procedure should clear >> any previous state that could exist in the controller registers. > > I'll add your patch to can/master and add stable on Cc. Looking forward > for some suspend/resume code :) Looking forward to writing suspend/resume code :). Some cred should go to Christian (added him to CC) for finding this problem and reporting it to me. -- Med Vänliga Hälsningar / Best Regards ******************************************************************* Mirza Krak Host Mobility AB mirza.krak@...tmobility.com Anders Personsgatan 12, 416 64 Göteborg Sweden http://www.hostmobility.com Direct: +46 31 31 32 704 Phone: +46 31 31 32 700 Fax: +46 31 80 67 51 Mobile: +46 730 28 06 22 ******************************************************************* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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