Re: [PATCHv3 5/7] dmaengine: dw_dmac: add PCI part of the driver

From: Vinod Koul
Date: Wed Oct 24 2012 - 07:27:03 EST


On Mon, 2012-10-08 at 18:57 +0530, Viresh Kumar wrote:
> I agree that there are some parts of your approach which might be having
> few advantages. But it is actually adding more complexity without much
> need of it. Logically speaking, we never had two devices for the same
> dma controller. We are adding them just to have pci over platform.. Which
> would mean the system become more and more complex..
>
> So, during run time...
> - there will be two device-driver binding loops.. Once for pci and then for
> platform
> - In suspend/resume... two devices will get into suspend, instead of one..
> - There might be other frameworks in kernel.. which react on struct device
> basis... they will get affected too..
> - You have larger image size for pci case. as you compile platform too..
>
> Just try to think from this perspective... we dont have two hardware devices
> in the system.... Ideally speaking there must be a struct device associated
> with a hardware device...
>
> @Arnd/Vinod: Can you guys throw some more light here.. on the adv/disadv
> of both the approaches?
I am worried about those tow. Runtime PM handlers in case PCI devices
make life a lot easier am not sure what support will be there for
platform devices in other systems.
Also next version of this h/w on our systems is bringing subtle changes
so having them separate seemed to me a better idea.


--
Vinod Koul
Intel Corp.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/