The original core KCS IRQ handling function 'kcs_bmc_handle_event' had a wrong logical desgin, it should force abort the KCS transaction only if the IBF flag is set, because multiple KCS channels share the same handle function; and it should return 0, which indicates that event of current channel is handled. An negative value -ENODATA will cause the IRQ handler of BMC KCS controller return IRQ_NONE, then IRQ moudle will treat this IRQ 'nobody cared', it will trigger IRQ exception.
irq 30: nobody cared (try booting with the "irqpoll" option) CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.15-npcm750 #1 Hardware name: NPCMX50 Chip family [<c010b264>] (unwind_backtrace) from [<c0106930>] (show_stack+0x20/0x24) [<c0106930>] (show_stack) from [<c03dad38>] (dump_stack+0x8c/0xa0) [<c03dad38>] (dump_stack) from [<c0168810>] (__report_bad_irq+0x3c/0xdc) [<c0168810>] (__report_bad_irq) from [<c0168c34>] (note_interrupt+0x29c/0x2ec) [<c0168c34>] (note_interrupt) from [<c0165c80>] (handle_irq_event_percpu+0x5c/0x68) [<c0165c80>] (handle_irq_event_percpu) from [<c0165cd4>] (handle_irq_event+0x48/0x6c) [<c0165cd4>] (handle_irq_event) from [<c0169664>] (handle_fasteoi_irq+0xc8/0x198) [<c0169664>] (handle_fasteoi_irq) from [<c016529c>] (__handle_domain_irq+0x90/0xe8) [<c016529c>] (__handle_domain_irq) from [<c01014bc>] (gic_handle_irq+0x58/0x9c) [<c01014bc>] (gic_handle_irq) from [<c010752c>] (__irq_svc+0x6c/0x90) Exception stack(0xc0a01de8 to 0xc0a01e30) 1de0: 00002080 c0a6fbc0 00000000 00000000 00000000 c096d294 1e00: 00000000 00000001 dc406400 f03ff100 00000082 c0a01e94 c0a6fbc0 c0a01e38 1e20: 00200102 c01015bc 60000113 ffffffff [<c010752c>] (__irq_svc) from [<c01015bc>] (__do_softirq+0xbc/0x358) [<c01015bc>] (__do_softirq) from [<c011c798>] (irq_exit+0xb8/0xec) [<c011c798>] (irq_exit) from [<c01652a0>] (__handle_domain_irq+0x94/0xe8) [<c01652a0>] (__handle_domain_irq) from [<c01014bc>] (gic_handle_irq+0x58/0x9c) [<c01014bc>] (gic_handle_irq) from [<c010752c>] (__irq_svc+0x6c/0x90) Exception stack(0xc0a01ef8 to 0xc0a01f40) 1ee0: 00000000 000003ae 1f00: dcc0f338 c0111060 c0a00000 c0a0cc44 c0a0cbe4 c0a1c22b c07bc218 00000001 1f20: dcffca40 c0a01f54 c0a01f58 c0a01f48 c0103524 c0103528 60000013 ffffffff [<c010752c>] (__irq_svc) from [<c0103528>] (arch_cpu_idle+0x48/0x4c) [<c0103528>] (arch_cpu_idle) from [<c0681390>] (default_idle_call+0x30/0x3c) [<c0681390>] (default_idle_call) from [<c0156f24>] (do_idle+0xc8/0x134) [<c0156f24>] (do_idle) from [<c015722c>] (cpu_startup_entry+0x28/0x2c) [<c015722c>] (cpu_startup_entry) from [<c067ad74>] (rest_init+0x84/0x88) [<c067ad74>] (rest_init) from [<c0900d44>] (start_kernel+0x388/0x394) [<c0900d44>] (start_kernel) from [<0000807c>] (0x807c) handlers: [<c041c5dc>] npcm7xx_kcs_irq Disabling IRQ #30 Signed-off-by: Haiyue Wang <haiyue.w...@linux.intel.com> --- Hi Corey, This patch looks introducing BIG modification, it should be easily understandable, and makes code clean & fix an error design, which is introduced by misunderstanding the IRQ return value. BR, Haiyue --- drivers/char/ipmi/kcs_bmc.c | 31 ++++++++++--------------------- 1 file changed, 10 insertions(+), 21 deletions(-) diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c index fbfc05e..bb882ab1 100644 --- a/drivers/char/ipmi/kcs_bmc.c +++ b/drivers/char/ipmi/kcs_bmc.c @@ -210,34 +210,23 @@ static void kcs_bmc_handle_cmd(struct kcs_bmc *kcs_bmc) int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc) { unsigned long flags; - int ret = 0; + int ret = -ENODATA; u8 status; spin_lock_irqsave(&kcs_bmc->lock, flags); - if (!kcs_bmc->running) { - kcs_force_abort(kcs_bmc); - ret = -ENODEV; - goto out_unlock; - } - - status = read_status(kcs_bmc) & (KCS_STATUS_IBF | KCS_STATUS_CMD_DAT); - - switch (status) { - case KCS_STATUS_IBF | KCS_STATUS_CMD_DAT: - kcs_bmc_handle_cmd(kcs_bmc); - break; - - case KCS_STATUS_IBF: - kcs_bmc_handle_data(kcs_bmc); - break; + status = read_status(kcs_bmc); + if (status & KCS_STATUS_IBF) { + if (!kcs_bmc->running) + kcs_force_abort(kcs_bmc); + else if (status & KCS_STATUS_CMD_DAT) + kcs_bmc_handle_cmd(kcs_bmc); + else + kcs_bmc_handle_data(kcs_bmc); - default: - ret = -ENODATA; - break; + ret = 0; } -out_unlock: spin_unlock_irqrestore(&kcs_bmc->lock, flags); return ret; -- 2.7.4 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Openipmi-developer mailing list Openipmi-developer@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openipmi-developer