[PATCH 05/10] ARM: s3c64xx: enable sparse IRQ support

On Wednesday 18 March 2015, Mark Brown wrote:

On Sun, Mar 08, 2015 at 10:42:59PM +0100, Arnd Bergmann wrote:

quoted

diff --git a/arch/arm/mach-s3c64xx/mach-crag6410.c b/arch/arm/mach-s3c64xx/mach-crag6410.c
index f395a5617142..cbe353a5450e 100644
--- a/arch/arm/mach-s3c64xx/mach-crag6410.c
+++ b/arch/arm/mach-s3c64xx/mach-crag6410.c

@@ -855,7 +855,7 @@ static void __init crag6410_machine_init(void)
 MACHINE_START(WLF_CRAGG_6410, "Wolfson Cragganmore 6410")
      /* Maintainer: Mark Brown <broonie@opensource.wolfsonmicro.com> */
      .atag_offset    = 0x100,
-     .nr_irqs        = S3C64XX_NR_IRQS + 160,
+     .nr_irqs        = S3C64XX_NR_IRQS,
      .init_irq       = s3c6410_init_irq,
      .map_io         = crag6410_map_io,
      .init_machine   = crag6410_machine_init,

quoted

The samsung-gpio driver does not allocate irq descriptors for itself
though, otherwise we could make the S3C64XX_NR_IRQS number smaller.

That's not the only thing, I'm still seeing an issue even with the
change above.  The VICs are also complaining about preallocated
descriptors, but they just assume the descriptors were preallocated and
carry on happily.

Yes, that is the behavior I expected to see. The VIC driver would be
fine in theory with allocating the descriptors dynamically, but
the secondary irqchip (s3c_irq_eint) would need significant changes.

IIRC, another problem is the way that the first NR_IRQS_LEGACY interrupts
are always preallocated, but would not need to, once we fix the eint.
	Arnd