On Fri, 2011-05-27 at 14:38 +0200, Cousson, Benoit wrote: > Hi Tomi, > > On 5/27/2011 9:38 AM, Valkeinen, Tomi wrote: > > Add omap_device_reset() function which can be used to reset the hwmods > > associated with the given platform device. > > We've never exposed it because we are trying to avoid that any driver > play with asynchronous HW reset. That can lead to undefined HW behavior :-( > > Do you have some strong need for that? DSS driver has been designed so that it resets the HW before it begins programming it. That way we get the HW into known state. Otherwise we need to be extra careful to program all possible registers to a sane value. Not impossible, of course, but requires extra work. I noticed the problem with DSI driver, it didn't work anymore if I didn't reset it. Why does it lead to undefined HW behaviour? Isn't it much better to reset the HW before starting to use it to be 100% sure it's in known and valid state? Especially in error situations it may be difficult (even impossible) to recover without reset. DISPC has been known to froze in some sync lost situations, and, if I recall right, if DSI transfer is aborted the only way to recover is to reset the DSI block (on OMAP3). Tomi -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
