From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Anholt Subject: Re: [PATCH RESEND] drm/vc4: Make sure to emit a tile coordinates between two MSAA loads. Date: Fri, 22 Mar 2019 14:28:04 -0700 Message-ID: <87imwa38gr.fsf@anholt.net> References: <20190206232550.12012-1-eric@anholt.net> <5c5ef4c7869f9294cfb7128a8b0ee00cf2012e40.camel@bootlin.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Return-path: In-Reply-To: <5c5ef4c7869f9294cfb7128a8b0ee00cf2012e40.camel@bootlin.com> Sender: linux-kernel-owner@vger.kernel.org To: Paul Kocialkowski , dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, Maxime Ripard List-Id: dri-devel@lists.freedesktop.org --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Paul Kocialkowski writes: > Hi, > > Le mercredi 06 f=C3=A9vrier 2019 =C3=A0 15:25 -0800, Eric Anholt a =C3=A9= crit : >> The HW only executes a load once the tile coordinates packet happens, >> and only tracks one at a time, so by emitting our two MSAA loads back >> to back we would end up with an undefined color or Z buffer. > > This change deals with things that I'm not very familiar with, but here > is my take on what is happening here: > > - When we have to do more than a single load in the same render command > list, we need to send out tile coordinates and a dummy store in between > the two, because of internal architecture requirements of the GPU; > - We're dealing with the color buffer first and then the z-stencil > buffer; > - As a result, we need to issue that dummy store in the block handling > the z-stencil, if there was a previous color load in the rcl; > - We previously only did that for non-MSAA z-stencil buffers (without > the FULL_RES flag); > - The same thing actually needs to be done for the MSAA case too, as > the reason why we need that dummy store also applies to MSAA loads. > > If my understanding is correct, then consider this: > Reviewed-by: Paul Kocialkowski This is all correct. Thanks! --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE/JuuFDWp9/ZkuCBXtdYpNtH8nugFAlyVU2UACgkQtdYpNtH8 nujq9A/9HbvDJ1hdn+1ZPs45CqL0EKn21SV067mXvQBjWWnH7bTk9R8Gi2Kf0W4Y 52T7ZtFz/m056VSYu0LC5pkdHBFR0OVs5OyTsjft5hZKwcJlZpxrTqDO1zeUAURF HfVMpV2cyFEdXLUwV5F9bw/3VNjJ1VFHON3fZzb7Au8OB6EdpTLhNGfepoVsbnnq WFU0CWyg30yQLIz2yDgCVk0Vrx/b8GJQtWxaPpKpn2wC9nYQ0XT9Skn7Hku766Rx Zct4LU4K2CrSnN2UwLXPRnFxSjSOUZLYoCOdO82uKfOwYQJOQwmsrJkWuAo7XeQZ bUaaZcRItY+f4GzhELQakUV2JMrDlgYy8V3S9S5UwN4UIhXX8Y327+jm93ewURs7 HbTw2xs3NHkaDfo0S8993AWSe12zifR2TjVGy9CbUbUz5fuIvIgf2tZCLG0zdszn lO836aJht2t2UXl6FNOrdDKlDzi5rAM6TMoT7uWCHzD0UY/UyYPkFciACHoM3pRm QcxkpnFu790NQlFHshkRgZjSVo7qpcHokjFhoJqfxsdNT/nsM2e6nOxClxjyNhAD q+xwg57R2XTev9Sqd4RrT70oFFEjPOD7AMy1nGjez9182te759XeBpiSzhZ89iHY J+tAhxDmJWIWHMDDVobqKpMCyuRQUhChhDXnZKRsO/oLpF/zOkA= =Kh8o -----END PGP SIGNATURE----- --=-=-=--