From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754549AbeCWKDu convert rfc822-to-8bit (ORCPT ); Fri, 23 Mar 2018 06:03:50 -0400 Received: from mail.bootlin.com ([62.4.15.54]:40428 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754507AbeCWKDm (ORCPT ); Fri, 23 Mar 2018 06:03:42 -0400 Date: Fri, 23 Mar 2018 11:03:30 +0100 From: Maxime Ripard To: Paul Kocialkowski Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, David Airlie , Chen-Yu Tsai , Daniel Vetter , Gustavo Padovan , Sean Paul Subject: Re: [PATCH 04/10] drm/sun4i: Explicitly list and check formats supported by the backend Message-ID: <20180323100330.2sijtsp5bdyyel5a@flea> References: <20180321152904.22411-1-paul.kocialkowski@bootlin.com> <20180321152904.22411-5-paul.kocialkowski@bootlin.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <20180321152904.22411-5-paul.kocialkowski@bootlin.com> User-Agent: NeoMutt/20180223 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 21, 2018 at 04:28:58PM +0100, Paul Kocialkowski wrote: > In order to check whether the backend supports a specific format, an > explicit list and a related helper are introduced. > > They are then used to determine whether the frontend should be used for > a layer, when the format is not supported by the backend. > > Signed-off-by: Paul Kocialkowski > --- > drivers/gpu/drm/sun4i/sun4i_backend.c | 48 ++++++++++++++++++++++++++++++++++- > drivers/gpu/drm/sun4i/sun4i_backend.h | 1 + > 2 files changed, 48 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c > index 274a1db6fa8e..7703ba989743 100644 > --- a/drivers/gpu/drm/sun4i/sun4i_backend.c > +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c > @@ -172,6 +172,39 @@ static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode) > return 0; > } > > +static const uint32_t sun4i_backend_formats[] = { > + /* RGB */ > + DRM_FORMAT_ARGB4444, > + DRM_FORMAT_RGBA4444, > + DRM_FORMAT_ARGB1555, > + DRM_FORMAT_RGBA5551, > + DRM_FORMAT_RGB565, > + DRM_FORMAT_RGB888, > + DRM_FORMAT_XRGB8888, > + DRM_FORMAT_BGRX8888, > + DRM_FORMAT_ARGB8888, > + /* YUV422 */ > + DRM_FORMAT_YUYV, > + DRM_FORMAT_YVYU, > + DRM_FORMAT_UYVY, > + DRM_FORMAT_VYUY, Ordering them by alphabetical order would be better. > +}; > + > +bool sun4i_backend_format_is_supported(uint32_t fmt) > +{ > + bool found = false; > + unsigned int i; > + > + for (i = 0; i < ARRAY_SIZE(sun4i_backend_formats); i++) { > + if (sun4i_backend_formats[i] == fmt) { > + found = true; > + break; return true? > + } > + } > + > + return found; > +} > + > int sun4i_backend_update_layer_coord(struct sun4i_backend *backend, > int layer, struct drm_plane *plane) > { > @@ -436,15 +469,28 @@ static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state) > { > struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane); > struct sun4i_backend *backend = layer->backend; > + struct drm_framebuffer *fb = state->fb; > > if (IS_ERR(backend->frontend)) > return false; > > + /* > + * Let's pretend that every format is either supported by the backend or > + * the frontend. This is not true in practice, as some tiling modes are > + * not supported by either. There is still room to check this later in > + * the atomic check process. Then I guess there these tiling modes will not be exposed and we won't ever get that far, wouldn't we? > + */ > + if (!sun4i_backend_format_is_supported(fb->format->format)) > + return true; Even though there's a comment, this is not really natural. We are checking whether the frontend supports the current plane_state, so it just makes more sense to check whether the frontend supports the format, rather than if the backend doesn't support them. Maxime -- Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com