On Wed, 2010-07-21 at 14:01 +0200, Michał Nazarewicz wrote: > What you are asking for is: > > cma=a=100M cma_map=*/*=a > > All devices will share the same region so that "if the video driver isn't > using the memory" then "something else can use it". (please excuse me quoting > you, it was stronger then me ;) ). Ok .. > Driver has to little information to say whether it really stopped using > memory. Maybe the next call will be to allocate buffers for frames and > initialise the chip? Sure, some “good enough” defaults can be provided > (and the framework allows that) but still platform architect might need > more power. I think your talking more about optimization .. You can take that into account .. > > (btw, these strings your creating yikes, talk about confusing ..) > > They are not that scary really. Let's look at cma: > > a=10M;b=10M > > Split it on semicolon: > > a=10M > b=10M > > and you see that it defines two regions (a and b) 10M each. I think your assuming a lot .. I've never seen the notation before I wouldn't assuming there's regions or whatever .. > As of cma_map: > > camera,video=a;jpeg,scaler=b > > Again split it on semicolon: > > camera,video=a > jpeg,scaler=b > > Now, substitute equal sign by "use(s) region(s)": > > camera,video use(s) region(s): a > jpeg,scaler use(s) region(s): b > > No black magic here. ;) It way too complicated .. Users (i.e. not programmers) has to use this .. > >> One of the purposes of the CMA framework is to make it let device > >> drivers completely forget about the memory management and enjoy > >> a simple API. > > > > The driver, and it's maintainer, are really the best people to know how > > much memory they need and when it's used/unused. You don't really want > > to architect them out. > > This might be true if there is only one device but even then it's not > always the case. If many devices need physically-contiguous memory > there is no way for them to communicate and share memory. For best > performance someone must look at them and say who gets what. How do you think regular memory allocation work? I mean there's many devices that all need different amounts of memory and they get along. Yet your saying it's not possible . Daniel -- Sent by an consultant of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>