Re: [PATCH 3/5] drm,kdb,kms: Add an enter argument to mode_set_base_atomic() API

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Tue, 12 Oct 2010 10:46:52 -0500
Jason Wessel <jason.wessel@windriver.com> wrote:

> On 10/12/2010 10:38 AM, Jesse Barnes wrote:
> > On Tue, 12 Oct 2010 07:49:59 -0500
> > Jason Wessel <jason.wessel@windriver.com> wrote:
> >
> >   
> >> Some devices such as the pre nv02 chips have enter and exit
> >> constraints where hardware compression must be turned off and
> >> re-enabled on resuming normal operations.
> >>
> >> This patch extends the mode_set_base_atomic() call to pass an argument
> >> to indicate if this is an entry or an exit from an atomic kernel mode
> >> set change.  Individual drm drivers can properly save and restore
> >> state accordingly.
> >>
> >> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
> >> CC: Jesse Barnes <jbarnes@virtuousgeek.org>
> >> CC: David Airlie <airlied@linux.ie>
> >> CC: dri-devel@lists.freedesktop.org
> >> ---
> >>  drivers/gpu/drm/drm_fb_helper.c             |    5 +++--
> >>  drivers/gpu/drm/i915/intel_display.c        |    4 ++--
> >>  drivers/gpu/drm/nouveau/nv04_crtc.c         |    2 +-
> >>  drivers/gpu/drm/nouveau/nv50_crtc.c         |    2 +-
> >>  drivers/gpu/drm/radeon/atombios_crtc.c      |    2 +-
> >>  drivers/gpu/drm/radeon/radeon_legacy_crtc.c |    2 +-
> >>  drivers/gpu/drm/radeon/radeon_mode.h        |    4 ++--
> >>  include/drm/drm_crtc_helper.h               |    3 ++-
> >>  8 files changed, 13 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> >> index 6a5e403..625a2d5 100644
> >> --- a/drivers/gpu/drm/drm_fb_helper.c
> >> +++ b/drivers/gpu/drm/drm_fb_helper.c
> >> @@ -263,7 +263,8 @@ int drm_fb_helper_debug_enter(struct fb_info *info)
> >>  			funcs->mode_set_base_atomic(mode_set->crtc,
> >>  						    mode_set->fb,
> >>  						    mode_set->x,
> >> -						    mode_set->y);
> >> +						    mode_set->y,
> >> +						    1);
> >>     
> >
> > An enum for the last arg would make this call much less mysterious. :)
> >
> >   
> Is there anything that is already predefined or would you prefer just
> true or false?
> 
> This could be changed to a bool because there are really only two
> states, entering and exiting.  If you provide some guidance on the
> preferred naming, I can re-spin the patch.

I was thinking:

enum mode_set_atomic {
	ENTER_KDB,
	EXIT_KDB,
};

or something similar (the name of the enum could probably be better).
Just having a number or true/false always makes me have to check the
function prototype. Having an enum means it's readable at the
callsite.  But this is really just a nitpick; bool args like this are a
pet peeve of mine. :)

-- 
Jesse Barnes, Intel Open Source Technology Center