Hi, On Tue, Feb 19, 2013 at 11:16:38AM -0800, Kevin Hilman wrote: [ ... ] > The other problem is the where reset is need during runtime. Again, > what are the specific examples here? The one I can think of off the top > of my head is I2C, where it's needed in certain error recovery > scenarios. right, I still have a theory that it's not needed in that case either, though I haven't had time to try that out. > Here, we need a way for the driver itself to initiate a full reset. > Maybe a new runtime PM hook like ->runtime_reset() as Felipe has > suggested (though I'm not yet sure runtime PM is the right place for > this, since it's not strictly related to runtime PM). Or, if these are right, I agree with you but I couldn't think of a better place. Maybe we need a reset hook in struct device itself (as I suggested on another mail) but I'm not sure Greg would take it, unless we have a damn good reason. > mostly corner-case, error recovery scenarios, maybe a a way force the > driver to remove itself and re-probe (which would trigger the > bus-notifier based reset) as Tony has suggested is the better approach. I don't think so. We certainly don't need to go through all memory allocations again. That will just cause unnecessary memory fragmentation. > The OMAP I2C driver is doing a reset and fully re-initializing itself, > so it seems the forced remove/probe is the right approach there. Any I must disagree here. Doing a reprobe of I2C every time there's an error condition is overkill. It means freeing struct omap_i2c_dev, freeing its IRQ, freeing the ioremapped area, changing mux configuration (due to pinctrl calls) just to do it all over again. Besides omap_i2c_probe() calls omap_i2c_init() which will do the full IP reset anyway. The difference is that calling omap_i2c_init() directly doesn't force us to free and reallocate all resources all over again. > one have the other use cases handy? dwc3 gets reset during probe() too, but that has an IP specific reset which doesn't need SYSCONFIG register for that. -- balbi
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