[RFC PATCH v2 1/4] drm: Introduce generic probe function for component based masters.

Liviu Dudau Liviu.Dudau at arm.com
Mon Oct 19 06:32:55 PDT 2015

On Mon, Oct 19, 2015 at 02:26:38PM +0100, Russell King - ARM Linux wrote:
> On Mon, Oct 19, 2015 at 02:02:58PM +0100, Liviu Dudau wrote:
> > On Mon, Oct 19, 2015 at 01:25:37PM +0100, Russell King - ARM Linux wrote:
> > > Please don't move this into here, it's completely inappropriate.  Just
> > > because something makes use of this does not mean they only support
> > > 32-bit DMA.  Besides, this has nothing to do with whether or not it's
> > > OF-based or not.
> > 
> > Understood. My thinking process was that component-based drivers are all
> > OF-enabled (how else do you make use of the framework?) and 32-bit DMA is
> > present in 2 out of 3 drivers that are converted, so it looks to be common
> > enough that adding it to armada would not hurt. It was all done in the name of
> > collecting common code in a single function.
> Which is an utterly crap reason.
> It's also not appropriate.  I'm really not sure why you think that moving
> this here would in any way be appropriate - from my point of view, the
> mere proposal is utterly insane.

The proposal is to collect similar code present in DRM drivers that act as
component masters in one place in order to reduce code duplication. I want to
add another DRM driver that will make use of the same code and did not see
any reason to copy paste one of the slightly similar versions that are now
peppered in the drivers/drm drivers.

Sorry for making you believe this is more than just code cleanup, but the cover
letter clearly stated in the title the intent.

> The "container" device does not do any DMA, so it's inappropriate for
> it to have DMA masks set or negotiated on it.  So, actually, no one
> should be setting the DMA mask for their container device.  It's wrong.
> What if we have a 64-bit OF based platform wanting to use the component
> helper, and they want to call this function?  You prevent them doing so
> by moving this into here, because they're then forced down to 32-bit DMA.
> Please, get rid of it, and leave this crappiness in the respective
> drivers.

OK, will do.

Best regards,

> -- 
> FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
> according to speedtest.net.

| I would like to |
| fix the world,  |
| but they're not |
| giving me the   |
 \ source code!  /

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