Re: [PATCH 6/6] dma/imx-sdma: check whether event_id0 < 32 when set event_mask

[Richard Zhao <richard.zhao@freescale.com>]

On Wed, Jan 11, 2012 at 09:16:17PM +0800, Shawn Guo wrote:
> On Wed, Jan 11, 2012 at 02:37:08PM +0800, Eric Miao wrote:
> > I think Richard has made the issue quite clear here, the original
> 
> Yes, he has made it clear, but only after I asked for more comments,
> not with the empty commit message.
> 
> > code does seem to have some problems even to me, who do not
> > understand the very details of the SDMA:
> > 
> > -                       sdmac->event_mask0 = 1 << sdmac->event_id0;
> > -                       sdmac->event_mask1 = 1 << (sdmac->event_id0 - 32);
> > 
> > 1. if sdmac->event_id0 >= 32, which will cause event_mask0 to be incorrect
> > 2. if sdmac->event_id < 32, sdmac->event_mask1 will be incorrect
> > 
> My testing tells this is not the case.  The event_mask0 will be 0 in
> case 1) and event_mask1 will be 0 in case 2), which is quite what we
> expect.  And I do not believe you will see any functionality bug with
> the existing code.
Please see my mail mentioned "we shoud not let it depends on gcc's
behavior."
> 
> See, that's why we need verbose commit message to make the patch and
> the problem it's trying to address very clear.
I never doubt it.

Thanks
Richard
> 
> Regards,
> Shawn
>