From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Anholt Subject: Re: [PATCH] drm/vc4: plane: Expand the lower bits using the LSB Date: Tue, 24 Apr 2018 09:53:28 -0700 Message-ID: <87604gtuk7.fsf@anholt.net> References: <20180424074814.6922-1-maxime.ripard@bootlin.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1654695846==" Return-path: Received: from anholt.net (anholt.net [50.246.234.109]) by gabe.freedesktop.org (Postfix) with ESMTP id C1D396E3F7 for ; Tue, 24 Apr 2018 16:53:31 +0000 (UTC) In-Reply-To: <20180424074814.6922-1-maxime.ripard@bootlin.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Cc: Maxime Ripard , dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============1654695846== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" --=-=-= Content-Type: text/plain Maxime Ripard writes: > The vc4 HVS uses an internal RGB888 representation of the frames, and will > by default expand formats using a lower depth using zeros. > > This causes an issue when we try to use other compositing software such as > pixman that seems to be filling the missing bits using the format least > significant bit value. As such, this prevents us from checking the display > output in a reliable way. I don't think this is the right expansion function, though? My understanding of proper unorm expansion, and what pixman's unorm_to_unorm() does, is that you replicate the value in the missing bits until you've filled them all (so SCALER_CTL0_EXPAND_REPEAT) --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE/JuuFDWp9/ZkuCBXtdYpNtH8nugFAlrfYQgACgkQtdYpNtH8 nuidrQ/9H3vUjbm1ZUVgaqgNmNWwidrOtIbwcPIzhy07X18QB1z+gRiwuDVawr48 0gxfxoU7OHVLUc8/0Qx/Mta6BbrZiVrTYV6oxNmBGZvsKn6+W8f5YtkQkHlH+kGY 74OJEyz27Gpm2zciKkfm+Ytk8QfBMZE+BJVUSHaC8TRY4ZsiOk9mVkEzLfYrQOSW 484CGYeBLu2EUMFUi9WRuj2ztz6cRt79dMhcVzdulwmIz6E5tj1LdP/ddi271Nfk BNFKjKKbhOJGNRBoFiyWQ9+Z+aNq1xSOJEqJASyEJ/+vx5ZNqTtf3+aGkwSbPgnE rfUlHhWxeuKk+aUhSmR0xUydwUcfBhA8KY+lTast0bhFQYsYNlSvj5cwe3Dy1Cs8 WJTOiiVlZ8gGGFHAW6+tJVPR12BCkXzOoEx1EfrncTpCPp3PUnX1quIbG1jBYzRW DfMh/s5EAKBIiYrAElSOEKtbLdSUpRSrL/9cZkHt0mVL9rqkrHdh3SR8pdYasrq3 50tjbiM2cB2dFrJRjieQZ79Ks3fIkO+Q19DJmbI1uZ2l4DItxnoEn3+z/uK5tji0 s+8vs65GiGSynFn7+XVINpaAqT2xJyMqp3ebWe/LrPVtNA9i/bQYOPQcMddAukby uXzyUhX7R1H4PcflZ/Yg7MGR+BoNkLUe2yN4k6PEdsmUrcaXQL0= =hpm2 -----END PGP SIGNATURE----- --=-=-=-- --===============1654695846== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVsCg== --===============1654695846==--