Subject: [alsa-devel] [PATCH] ASoC: fsl-ssi: fix SDMA starvation

From: [email-masked] (Timur Tabi)
Date: Wed, 13 Nov 2013 07:10:49 -0600

Markus Pargmann wrote:
>> >Can you change the code so that the interrupts are enabled only on
>> >i.MX?  On PowerPC, the interrupts are used only for debugging.

> Why is this necessary? The interrupts were enabled for all
> architectures before.

My concern is with these lines:

	write_ssi_mask(&ssi->sier, 0, CCSR_SSI_SIER_TDMAE);
...
	write_ssi_mask(&ssi->sier, CCSR_SSI_SIER_TDMAE, 0);

This toggles the TDMAE interrupt on PowerPC, which I believe is VITAL to 
making it work.  The SSI and the DMA controller talk to each other 
automatically, and if I'm reading the documentation correctly, that 
communication depends on TDMAE and RDMAE.