From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.bootlin.com ([62.4.15.54]:59547 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726133AbeKHTQg (ORCPT ); Thu, 8 Nov 2018 14:16:36 -0500 Date: Thu, 8 Nov 2018 10:41:55 +0100 From: Boris Brezillon To: Eric Anholt Cc: stable@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 1/3] drm/vc4: Set PPF scaling when the source image is only vertically scaled Message-ID: <20181108104155.63b367c9@bbrezillon> In-Reply-To: <87r2fwyfwt.fsf@anholt.net> References: <20181024100505.22436-1-boris.brezillon@bootlin.com> <20181024170238.4f65f5f2@bbrezillon> <87r2fwyfwt.fsf@anholt.net> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: stable-owner@vger.kernel.org List-ID: On Wed, 07 Nov 2018 09:08:02 -0800 Eric Anholt wrote: > Boris Brezillon writes: > > > On Wed, 24 Oct 2018 12:05:03 +0200 > > Boris Brezillon wrote: > > > >> The source image might be only vertically scaled, and in this case > >> ->is_unity will be false, but we'd still have to force ->x_scaling[0] > >> to VC4_SCALING_PPF for YUV conversion to work properly. > >> > >> Let's replace the ->is_unity test by->x_scaling[0] == VC4_SCALING_NONE > >> to cope with that. > >> > >> Fixes: 658d8cbd07da ("drm/vc4: Fix the "no scaling" case on multi-planar YUV formats") > >> Cc: > >> Signed-off-by: Boris Brezillon > >> --- > >> drivers/gpu/drm/vc4/vc4_plane.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c > >> index 60d5ad19cedd..32b7b9f47c5d 100644 > >> --- a/drivers/gpu/drm/vc4/vc4_plane.c > >> +++ b/drivers/gpu/drm/vc4/vc4_plane.c > >> @@ -318,7 +318,7 @@ static int vc4_plane_setup_clipping_and_scaling(struct drm_plane_state *state) > >> * even on a plane that's otherwise 1:1. Looks like only PPF > >> * works in that case, so let's pick that one. > >> */ > >> - if (vc4_state->is_unity) > >> + if (vc4_state->x_scaling[0] == VC4_SCALING_NONE) > >> vc4_state->x_scaling[0] = VC4_SCALING_PPF; > > > > Actually, I'm not sure about this patch is needed. According to the > > spec, we should not enable the scaler on the Y channel when ->is_unity > > is true. > > I tested it, and it seems to work if we just leave x_scaling[0] to > > VC4_SCALING_NONE. > > Sorry, I've been delaying on this series until I could spend some time > looking at the spec. > > I think you're right, I see no reason to kick us out of is_unity for > YUV -- you can have is_unity, Y unscaled, and UV scaled. Okay, so I'll just remove if (vc4_state->x_scaling[0] == VC4_SCALING_NONE) vc4_state->x_scaling[0] = VC4_SCALING_PPF; What about the 2 other patches in this series? Patch 2 is fixing a real bug, patch 3 is not fixing a bug, but according to the spec PPF is better when the downscaling ratio is small.