[PATCH 1/8] staging: tidspbridge - remove req_addr from proc_map

[Guzman Lugo, Fernando]

> -----Original Message-----
> From: Felipe Contreras [mailto:felipe.contreras at nokia.com] 
> Sent: Tuesday, October 26, 2010 2:38 PM
> To: Guzman Lugo, Fernando; felipe.contreras at gmail.com
> Cc: gregkh at suse.de; hiroshi.doyu at nokia.com; 
> linux-kernel at vger.kernel.org; andy.shevchenko at gmail.com; 
> linux-omap at vger.kernel.org; linux-arm-kernel at lists.infradead.org
> Subject: RE: [PATCH 1/8] staging: tidspbridge - remove 
> req_addr from proc_map
> 
> fernando.lugo at ti.com wrote:
> > > fernando.lugo at ti.com wrote:
> > > > > On Tue, Oct 26, 2010 at 3:51 AM, Fernando Guzman Lugo 
> > > > > <x0095840 at ti.com> wrote:
> > > > > > The device address is assigned by tidspbridge no need for
> > > > > that parameter anymore.
> > > > > >
> > > > > > Signed-off-by: Fernando Guzman Lugo <x0095840 at ti.com>
> > > > > 
> > > > > This would break the API with user-space, right?
> > > > 
> > > > Yes, user-space needs to be changed accordingly.
> > > 
> > > Wouldn't it make sense to avoid stuffing so many changes at once 
> > > including ABI breakage?
> > > 
> > > Does user-space really _needs_ to be changed? Can't you 
> just ignore 
> > > that argument?
> > 
> > Actually, I had a previous version of that patch where I 
> only Ignored 
> > that paramteter. But after thinking again and seeing How 
> the long time 
> > ago depreacted function are still there I Removed the parameter in 
> > order to force apps to make the change.
> 
> Again, can we concentrate on first getting this thing to work?

If to make it work for 37 the iommu migration patch will be revert
These set of patches will have to wait until the patches are merged
Again. So the dspbridge would be "fix" first a then the patches would
Be merged.

> 
> We can think on breaking things again later.
> 
> > You can ignore that argument at API level, so all users of 
> the API not 
> > need to have change (in that momment). That should be Only few line 
> > change.
> 
> Yes, that's what I'm proposing.

I meant userspace api or library level:
Example:

Dsp_proc_map(proc, mpu_addr, req_addr, *dsp_addr, attr) {
...
	struct proc_map args = {
		.map_addr = mpu_addr;
		/* ignore req_addr */
		.dsp_addr = dsp_addr;
		.attr = attr;
	}

	ret = ioctl(handle, PROCMAP_CMD, args)
...
}


> 
> > > > > I think this change should be delayed, preferably 
> after we have 
> > > > > a working tidspbridge.
> > > > 
> > > > The issue you were seeing must be fixed with patch 2/8, and
> > > Having all
> > > > the dependencies tidspbridge has to be working Properly.
> > > 
> > > Yes, which might not happen at .37. If we revert the 
> iommu stuff, we 
> > > might have a chance at having a working bridge on .37.
> > 
> > But havi that merged in tidspbridge make more pressure to 
> merged The 
> > dependencies, if not maybe that wont have event for .38.
> 
> Those patches have been there for a while and there's no sign 
> of when they'll be merged. Also, remember that the fact that 
> the patches have been sent doesn't guarantee they would be on 
> this, or even the next cycle.
> 
> Besides, the rule followed here is: it's ready when it's 
> ready. In the meantime the driver should work, and we can do 
> that rather easily.

I don't have much experience in this kind of situacion if it is
believed it is the best solution then ok for me.

> 
> > But That is just my opinion if you all are agree revert is the best 
> > Option I am ok, but I looks like more work reverting and rebaseing 
> > specially because it is a big change.
> 
> git makes this easy.

Till we need to fix all the conflics, make sure everything work
Properly and then send it again to review. That can take a while,
But it seems someone else is agree to revert the changes, so maybe
That is the best to do in this situacion.

Thanks and regards,
Fernando.

> 
> The hard part is for the people out there that are trying to 
> use this driver and have to hunt mailing lists and multiple 
> repos just to get this to work. Moving to staging was 
> supposed to make this easier, not harder.
> 
> --
> Felipe Contreras
>