Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755574AbcKOI1j (ORCPT ); Tue, 15 Nov 2016 03:27:39 -0500 Received: from mga05.intel.com ([192.55.52.43]:12352 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751567AbcKOI1g (ORCPT ); Tue, 15 Nov 2016 03:27:36 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,641,1473145200"; d="scan'208";a="786572750" From: Jani Nikula To: David Weinehall Cc: Tomeu Vizoso , linux-kernel@vger.kernel.org, David Airlie , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Thierry Reding , Daniel Vetter Subject: Re: [Intel-gfx] [PATCH v11 3/4] drm/i915: Use new CRC debugfs API In-Reply-To: <20161115071609.GI8202@suiko.acc.umu.se> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <1475767268-14379-1-git-send-email-tomeu.vizoso@collabora.com> <1475767268-14379-4-git-send-email-tomeu.vizoso@collabora.com> <87inrq2vee.fsf@intel.com> <20161115071609.GI8202@suiko.acc.umu.se> Date: Tue, 15 Nov 2016 10:27:33 +0200 Message-ID: <87a8d12lmy.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2109 Lines: 53 On Tue, 15 Nov 2016, David Weinehall wrote: > On Mon, Nov 14, 2016 at 12:44:25PM +0200, Jani Nikula wrote: >> On Thu, 06 Oct 2016, Tomeu Vizoso wrote: >> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c >> > index 23a6c7213eca..7412a05fa5d9 100644 >> > --- a/drivers/gpu/drm/i915/intel_display.c >> > +++ b/drivers/gpu/drm/i915/intel_display.c >> > @@ -14636,6 +14636,7 @@ static const struct drm_crtc_funcs intel_crtc_funcs = { >> > .page_flip = intel_crtc_page_flip, >> > .atomic_duplicate_state = intel_crtc_duplicate_state, >> > .atomic_destroy_state = intel_crtc_destroy_state, >> > + .set_crc_source = intel_crtc_set_crc_source, >> > }; >> > >> > /** >> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h >> > index 737261b09110..31894b7c6517 100644 >> > --- a/drivers/gpu/drm/i915/intel_drv.h >> > +++ b/drivers/gpu/drm/i915/intel_drv.h >> > @@ -1844,6 +1844,14 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state); >> > /* intel_pipe_crc.c */ >> > int intel_pipe_crc_create(struct drm_minor *minor); >> > void intel_pipe_crc_cleanup(struct drm_minor *minor); >> > +#ifdef CONFIG_DEBUG_FS >> > +int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name, >> > + size_t *values_cnt); >> > +#else >> > +static inline int intel_crtc_set_crc_source(struct drm_crtc *crtc, >> > + const char *source_name, >> > + size_t *values_cnt) { return 0; } >> > +#endif >> >> "inline" here doesn't work because it's used as a function pointer. >> >> Is it better to have a function that returns 0 for .set_crc_source, or >> to set .set_crc_source to NULL when CONFIG_DEBUG_FS=n? > > I'd say that whenever we have a function pointer we should have a dummy > function without side-effects for this kind of things. Whoever calls .set_crc_source could do smarter things depending on the hook not being there vs. just silently plunging on. BR, Jani. > > > Kind regards, David -- Jani Nikula, Intel Open Source Technology Center