Re: [PATCH] drm/tegra: Remove of_dma_configure() from host1x_device_add()

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Feb 01, 2024 at 07:35:24PM +0000, Jon Hunter wrote:
> > You mean this sequence?
> > 
> > 		err = device_add(&ctx->dev);
> > 		if (err) {
> > 			dev_err(host1x->dev, "could not add context device %d: %d\n", i, err);
> > 			put_device(&ctx->dev);
> > 			goto unreg_devices;
> > 		}
> > 
> > 		err = of_dma_configure_id(&ctx->dev, node, true, &i);
> > 		if (err) {
> > 			dev_err(host1x->dev, "IOMMU configuration failed for context device %d: %d\n",
> > 				i, err);
> > 			device_unregister(&ctx->dev);
> > 			goto unreg_devices;
> > 		}
> 
> Yes this sequence.
> 
> > I didn't seem an obvious place that this would get fixed up later?
> > 
> > device_add() was done before so the iommu_device_link() shouldn't be
> > failing? Are you hitting a duplicate link (ie remove the nowarn from
> > iommu_device_link())
> 
> 
> Removing the '_nowarn' does appear to fix it, although it is not clear to me
> why?

What did you do to remove? Just the letters or the whole line?

I was thinking the letters because it triggers a large debug message.

But, what is the actual log output you see, is it -EEXIST?

If it is coming and going is it a race of some kind?

Jason