On Sun, 2005-09-11 at 05:56 +0200, ak@xxxxxx wrote: > >> Naturally, aic94xx has _no limitations_. :-) But hey, our hardware just > >> kicks a*s! > > > > That's very nice for you - but lets face it, a SAS layer > > that'll be unable to also deal with the El-Cheapo brand > > controllers isn't going to be very useful. > > Nobody knows what these bu^wlimitations will be though. So you cannot > really plan for them in advance. When someone writes drivers for such > limited hardware they can add code to handle the limitations. But it > seems reasonable to start with a clean hardware model, and only > add the hacks later when they are really needed and the requirements > are understood. But my point was that we already have a mechanism for coping with this: The scsi template parameterises some of these things (max sector size, sg table elements, clustering, etc). For less standard things it doesn't cover the driver uses the blk_ adjustors directly from slave_alloc/slave_configure (This is currently how USB and firewire communicate their alignment requirements). By wrappering both the template and the slave_alloc/slave_configure methods in the SAS class and not providing the driver access, it can't use existing methods to make any adjustments that may be necessary. James - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
