Grygorii Strashko <grygorii.strashko@xxxxxx> writes: > From: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> > > Currently, runtime PM is used to keep the device enabled only during > active transfers and for a configurable runtime PM autosuspend timout > after an xfer. > > In addition to idling the device, driver's ->runtime_suspend() method > currently disables device interrupts when idle. However, on some SoCs > (notably OMAP4+), the I2C hardware may shared with other coprocessors. > This means that the MPU will still recieve interrupts if a coprocessor > is using the I2C device. To avoid this, also disable interrupts at > the MPU INTC when idling the device in ->runtime_suspend() (and > re-enable them in ->runtime_resume().) This part based on an original > patch from Shubhrajyoti Datta. NOTE: for proper sharing the I2C with > a coprocessor, this driver still needs hwspinlock support added. > > More over, this patch fixes the kernel boot failure which happens when > CONFIG_SENSORS_LM75=y: > > [ 2.251220] WARNING: at drivers/bus/omap_l3_noc.c:113 l3_interrupt_handler+0x140/0x184() > [ 2.257781] L3 custom error: MASTER:MPU TARGET:L4 PER2 > [ 2.264373] Modules linked in: > [ 2.268463] CPU: 0 PID: 2 Comm: kthreadd Not tainted 3.10.0-rc4-00034-g042dd60-dirty #64 > [ 2.270385] [<c001a80c>] (unwind_backtrace+0x0/0xf0) from [<c0017238>] (show_stack+0x10/0x14) > [ 2.286102] [<c0017238>] (show_stack+0x10/0x14) from [<c0040fd0>] (warn_slowpath_common+0x4c/0x68) > [ 2.295593] [<c0040fd0>] (warn_slowpath_common+0x4c/0x68) from [<c0041080>] (warn_slowpath_fmt+0x30/0x40) > [ 2.299987] [<c0041080>] (warn_slowpath_fmt+0x30/0x40) from [<c02c5ed0>] (l3_interrupt_handler+0x140/0x184) > [ 2.315582] [<c02c5ed0>] (l3_interrupt_handler+0x140/0x184) from [<c009ffb8>] (handle_irq_event_percpu+0x58/0x258) > [ 2.323364] [<c009ffb8>] (handle_irq_event_percpu+0x58/0x258) from [<c00a01f4>] (handle_irq_event+0x3c/0x5c) > [ 2.327819] [<c00a01f4>] (handle_irq_event+0x3c/0x5c) from [<c00a2f7c>] (handle_fasteoi_irq+0xbc/0x164) > [ 2.337829] [<c00a2f7c>] (handle_fasteoi_irq+0xbc/0x164) from [<c009f978>] (generic_handle_irq+0x20/0x30) > [ 2.357513] [<c009f978>] (generic_handle_irq+0x20/0x30) from [<c0014168>] (handle_IRQ+0x4c/0xac) > [ 2.366821] [<c0014168>] (handle_IRQ+0x4c/0xac) from [<c00085b4>] (gic_handle_irq+0x28/0x5c) > [ 2.375762] [<c00085b4>] (gic_handle_irq+0x28/0x5c) from [<c04f08a4>] (__irq_svc+0x44/0x5c) > [ 2.379821] Exception stack(0xdb085ec0 to 0xdb085f08) > [ 2.389953] 5ec0: 00000001 00000001 00000000 db07ea00 40000113 db2317a8 db084000 000002f1 > [ 2.389953] 5ee0: db07ea00 00000000 00000000 00000000 c04fd990 db085f08 c009170c c04f03e8 > [ 2.405609] 5f00: 20000113 ffffffff > [ 2.408355] [<c04f08a4>] (__irq_svc+0x44/0x5c) from [<c04f03e8>] (_raw_spin_unlock_irqrestore+0x34/0x44) > [ 2.418304] [<c04f03e8>] (_raw_spin_unlock_irqrestore+0x34/0x44) from [<c00403c0>] (do_fork+0xa4/0x2d4) > [ 2.427795] [<c00403c0>] (do_fork+0xa4/0x2d4) from [<c0040620>] (kernel_thread+0x30/0x38) > [ 2.437805] [<c0040620>] (kernel_thread+0x30/0x38) from [<c0063888>] (kthreadd+0xd4/0x13c) > [ 2.448364] [<c0063888>] (kthreadd+0xd4/0x13c) from [<c0013308>] (ret_from_fork+0x14/0x2c) > [ 2.448364] ---[ end trace da8cf92c433d1616 ]--- > > The root casue of crash is race between omap_i2c_runtime_suspend() > and omap_i2c_isr_thread() If there's a race here, then it's not the same problem which is described above, unless the CPU2 IRQ is happening because of a shared user of I2C, in which case it doesn't need any additional explanation. > > CPU1: CPU2: > |-omap_i2c_xfer | > |- pm_runtime_put_autosuspend() | > |-timeout |-omap_i2c_isr() > |-return IRQ_WAKE_THREAD; > |-omap_i2c_runtime_suspend() | > |-omap_i2c_isr_thread() > |- oops is here - I2C module is in idle state If this is happening, I don't think it's related to $SUBJECT patch (but is probably hidden by it.) Instead, what probably needs to happen in this is case is that omap_i2c_isr() should be doing a "mark last busy" to reset the autosuspend timeout. And, that should be done in a separate patch. > Cc: Nishanth Menon <nm@xxxxxx> > Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxx> Both the From: and Signed-off should be from my TI address since the work was done while I was working for TI. Also, if you change the original patch/changelog, you should add a line here like: [grygorii.strashko@xxxxxx]: updated changlog > Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
