On Thu, Dec 19, 2013 at 12:51:29PM +0200, Andy Shevchenko wrote: > On Wed, 2013-12-18 at 21:19 +0530, Vinod Koul wrote: > > On Mon, Dec 16, 2013 at 01:51:47PM +0530, Chew, Chiau Ee wrote: > > > > As mentioned by Andy, we are using *_noirq verion of suspend/resume PM > > > callback whereby the callbacks would be executed after IRQ handlers have > > > been > > > disabled. If using SET_SYSTEM_SLEEP_PM_OPS, it would be the normal > > > suspend/resume PM callback. Looking at the Desginware DMAC platform code > > > (drivers/dma/dw/platform.c), it is using the *_noirq suspend/resume PM > > > callback. Is it advisable to use the normal suspend/resume PM callback > > > instead > > > of *_noirq suspend/PM callback? > > > > i dont see a reason why we need the noirq versions > > Okay. I imagine the following use case. > > For example we have compiled in DMA driver (dw_dmac) along with, for > example, SPI driver. > > System was scheduled to go sleep. > > An order of calling IIUC might be DMA first, then SPI (since they are > not in parent / child relations). > > What was happened when SPI would like to do a DMA transfer and DMA is > going to sleep? I'm trying to understand if this is a case. In that case how does no irq version help us?
For these cases, I have been using suspend_late. Since the dmaengine driver is providing service to other clients (SPI), it needs to esnure that it suspends after SPI using suspend_late and resume using resume_early. That way dma is availble whenever the client is active -- ~Vinod > > > > > How about SET_SYSTEM_SLEEP_PM_OPS instead? > > > > > > So, we are using *_noirq versions of the functions here. What happened > > > when we switch to normal ones? Any side effects? > > > > -- > Andy Shevchenko <andriy.shevche...@linux.intel.com> > Intel Finland Oy > -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
