[igt-dev] [PATCH i-g-t 07/10] lib/psr: Drop support to old kernels without new PSR debugfs interface

[Souza, Jose]

On Tue, 2019-01-15 at 21:21 -0800, Dhinakaran Pandiyan wrote:
> On Fri, 2019-01-11 at 17:46 -0800, José Roberto de Souza wrote:
> > The nexts patches will add PSR2 tests and for that we need the new
> > PSR debugfs interface that was released in kernel 4.20 so it will
> > not
> > break for any updated system and we can drop support to the old
> > debugsfs and the support to kernels without even a debugfs
> > interface.
> 
> Can't we have psr_set(mode == PSR_MODE_2) skip if the kernel does not
> support the new interface?

We could but why keep supporting old kernels? My experience of running
a newer IGT over a old kernel or on the contrary was always
problematic.
	

> 
> 
> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  lib/igt_psr.c | 35 +++++++----------------------------
> >  1 file changed, 7 insertions(+), 28 deletions(-)
> > 
> > diff --git a/lib/igt_psr.c b/lib/igt_psr.c
> > index c6638c2c..5cc0fbc2 100644
> > --- a/lib/igt_psr.c
> > +++ b/lib/igt_psr.c
> > @@ -73,27 +73,7 @@ static int has_psr_debugfs(int debugfs_fd)
> >  	 * -ENODEV is returned when PSR is unavailable.
> >  	 */
> >  	ret = psr_write(debugfs_fd, "0xf");
> > -	if (ret == -EINVAL)
> > -		return 0;
> > -	else if (ret < 0)
> > -		return ret;
> > -
> > -	/* legacy debugfs api, we enabled irqs by writing, disable
> > them. */
> > -	psr_write(debugfs_fd, "0");
> > -	return -EINVAL;
> > -}
> > -
> > -static bool psr_modparam_set(int val)
> > -{
> > -	static int oldval = -1;
> > -
> > -	igt_set_module_param_int("enable_psr", val);
> > -
> > -	if (val == oldval)
> > -		return false;
> > -
> > -	oldval = val;
> > -	return true;
> > +	return ret == -EINVAL ? 0 : ret;
> >  }
> >  
> >  static int psr_restore_debugfs_fd = -1;
> > @@ -109,16 +89,15 @@ static bool psr_set(int debugfs_fd, bool
> > enable)
> >  
> >  	ret = has_psr_debugfs(debugfs_fd);
> >  	if (ret == -ENODEV) {
> > -		igt_skip_on_f(enable, "PSR not available\n");
> > +		igt_skip("PSR not available\n");
> > +		return false;
> > +	} else if (ret) {
> > +		igt_skip("PSR debugfs interface not available\n");
> >  		return false;
> >  	}
> >  
> > -	if (ret == -EINVAL) {
> > -		ret = psr_modparam_set(enable);
> > -	} else {
> > -		ret = psr_write(debugfs_fd, enable ? "0x3" : "0x1");
> > -		igt_assert(ret > 0);
> > -	}
> > +	ret = psr_write(debugfs_fd, enable ? "0x3" : "0x1");
> > +	igt_assert(ret > 0);
> >  
> >  	/* Restore original value on exit */
> >  	if (psr_restore_debugfs_fd == -1) {
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