On Wed, Feb 29, 2012 at 05:25:06PM +0200, Tero Kristo wrote:

Currently PRCM chain handler for OMAP4 requires SPARSE_IRQ to be enabled
from kernel config, however enabling this option breaks the OMAP kernel
completely and it can't be used.

No it does not.  Look:

	irq_alloc_descs(start, from, num, -1)

will allocate num interrupt descriptors from within from..NR_IRQS if
sparse IRQ is disabled.  So, provided there is sufficient space within
the available NR_IRQS, irq_alloc_descs() works for non-sparse IRQ.
There is no need to get rid of it at all.

If start is -1, then it will allocate from where-ever it can in the
range from..NR_IRQS.  Otherwise, it will fail if it can't get an
allocation starting at 'start'.

If sparse IRQ is enabled, then it will start allocating from whatever
the last figure output from the:

	NR_IRQS:%d nr_irqs:%d %d

line.