Dreamcast DMA

[Adrian M. <ad...@ne...>]

I think I have been over this before, but cannot find the emails on any
search...

The Dreamcast afaics is a plain SH7750 machine and this is what the
kernel configuration says:

CONFIG_NR_ONCHIP_DMA_CHANNELS:
This allows you to specify the number of channels that the on-chip
DMAC supports. This will be 4 for SH7750/SH7751 and 8 for the
SH7750R/SH7751R.                                                                                                                                     

Yet if you actually set this to 4 the DC won't boot, but it will boot if
set to 8.

On top of this, I am trying to get the pvr2 driver to work properly now
and it fails here....

#ifdef CONFIG_SH_DMA
	if (request_dma(pvr2dma, "pvr2") != 0) {
		printk(KERN_ERR "PVR2 failed to get DMA channel\n");
		free_irq(HW_EVENT_VSYNC, 0);
		return -EBUSY;
	}
#endif

pvr2dma is static unsigned int pvr2dma = ONCHIP_NR_DMA_CHANNELS;

And ONCHIP_NR_DMA_CHANNELS is #define ONCHIP_NR_DMA_CHANNELS  4 for a
Dreamcast

Is the documentation just wrong and should ONCHIP_NR_DMA_CHANNELS simply
be 8?