On Tuesday 27 October 2009 16:00:00 ext Jarkko Nikula wrote: > On Tue, 27 Oct 2009 13:07:23 +0200 > > Eero Nurkkala <[email protected]> wrote: > > Otherwise, that spinlocking is highly unnecessary and things are > > far better without than with it. The only case it could be useful > > is in SMPs, but OMAPs are not such quite yet - and when they > > are, things will need to be re-though anyway. > > Following commit is suggesting that mcbsp code *must* be SMP safe > already now: > > commit a5b92cc348299c20be215b9f4b50853ecfbf3864 > Author: Syed Rafiuddin <[email protected]> > Date: Tue Jul 28 18:57:10 2009 +0530 > > ARM: OMAP4: Add McBSP support
Yeah, but I think this locking issue has nothing to do with SMP safe or not. On playback start in omap_mcbsp_request the mcbsp->free is cleared. Further modification to the dma_op_mode in dma_op_mode_store is not allowed if the mcbsp port is in use, thus the dma_op_mode is protected against change while the port is in use (ensuring that the mode is same in omap34xx_mcbsp_request and omap_mcbsp_get_dma_op_mode functions). This alone makes the use of spinlock around the dma_op_mode unnecessary. -- Péter -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
