On 2012-04-04 17:23, Arnd Bergmann wrote: > On Wednesday 04 April 2012, Rafal Prylowski wrote: >>> >>> According to ATA specification, maximum IORDY pulse width is 1250ns, >>> so I'll set timeout to 2ms (I should check this before posting the driver..). >> >> 2ms is far too big value... Should be 2us. > > Ok, in this case, don't use jiffies. I guess it was already flawed because > jiffies doesn't get updated while you are in an interrupt handler. > > You could use ktime_get to get a high-resolution time stamp to compare to, > but it depends on how accurate your clocksource is. Jiffies seem to work. I was wrong with this interrupt handler. Actually IDE register read/write (and IORDY polling) is called from softirq, this is only triggered by interrupt. I hope this backtrace confirm this: BUG: scheduling while atomic: swapper/0/0x40000100 [<c000cb8c>] (unwind_backtrace+0x0/0xf4) from [<c023e1c4>] (__schedule+0x2e0/0x3 30) [<c023e1c4>] (__schedule+0x2e0/0x330) from [<c0033740>] (__cond_resched+0x24/0x3 4) [<c0033740>] (__cond_resched+0x24/0x34) from [<c023e2a4>] (_cond_resched+0x38/0x 40) [<c023e2a4>] (_cond_resched+0x38/0x40) from [<c016d64c>] (ep93xx_pata_wait_for_i ordy+0x20/0x64) [<c016d64c>] (ep93xx_pata_wait_for_iordy+0x20/0x64) from [<c016da5c>] (ep93xx_pa ta_read+0xac/0xb4) [<c016da5c>] (ep93xx_pata_read+0xac/0xb4) from [<c016daa8>] (ep93xx_pata_check_s tatus+0x1c/0x28) [<c016daa8>] (ep93xx_pata_check_status+0x1c/0x28) from [<c016cfa4>] (T.508+0x3c/ 0xf0) [<c016cfa4>] (T.508+0x3c/0xf0) from [<c016d2bc>] (ata_bmdma_qc_issue+0x50/0x19c) [<c016d2bc>] (ata_bmdma_qc_issue+0x50/0x19c) from [<c015c2ac>] (ata_qc_issue+0x1 98/0x2f8) [<c015c2ac>] (ata_qc_issue+0x198/0x2f8) from [<c0160c20>] (ata_scsi_translate+0x 98/0x178) [<c0160c20>] (ata_scsi_translate+0x98/0x178) from [<c0164514>] (ata_scsi_queuecm d+0x7c/0x230) [<c0164514>] (ata_scsi_queuecmd+0x7c/0x230) from [<c0149750>] (scsi_dispatch_cmd +0xd8/0x1b4) [<c0149750>] (scsi_dispatch_cmd+0xd8/0x1b4) from [<c014ee5c>] (scsi_request_fn+0 x308/0x378) [<c014ee5c>] (scsi_request_fn+0x308/0x378) from [<c00fb9b4>] (__blk_run_queue+0x 18/0x1c) [<c00fb9b4>] (__blk_run_queue+0x18/0x1c) from [<c00fb9f4>] (blk_run_queue+0x14/0 x1c) [<c00fb9f4>] (blk_run_queue+0x14/0x1c) from [<c014e574>] (scsi_run_queue+0xc0/0x 208) [<c014e574>] (scsi_run_queue+0xc0/0x208) from [<c014f084>] (scsi_next_command+0x 2c/0x38) [<c014f084>] (scsi_next_command+0x2c/0x38) from [<c014fa54>] (scsi_io_completion +0x258/0x56c) [<c014fa54>] (scsi_io_completion+0x258/0x56c) from [<c0102024>] (blk_done_softir q+0x80/0x98) [<c0102024>] (blk_done_softirq+0x80/0x98) from [<c0018af8>] (__do_softirq+0x94/0 x150) [<c0018af8>] (__do_softirq+0x94/0x150) from [<c0018d00>] (irq_exit+0x48/0x50) [<c0018d00>] (irq_exit+0x48/0x50) from [<c00097c0>] (handle_IRQ+0x34/0x84) [<c00097c0>] (handle_IRQ+0x34/0x84) from [<c000849c>] (vic_handle_irq+0x94/0xd4) [<c000849c>] (vic_handle_irq+0x94/0xd4) from [<c0008c14>] (__irq_svc+0x34/0x40) Sorry for the mess. I'm doing kernel development only occasionally... I changed msecs_to_jiffies() to usecs_to_jiffies(). Is it possible that ktime_get() give us better resolution? Thanks for all hints. RP -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
