From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH] drm/vc4: plane: Expand the lower bits using the LSB Date: Mon, 14 May 2018 15:20:46 +0200 Message-ID: <20180514132046.x3k65splrawenniv@flea> References: <20180424074814.6922-1-maxime.ripard@bootlin.com> <87604gtuk7.fsf@anholt.net> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0129832244==" Return-path: Received: from mail.bootlin.com (mail.bootlin.com [62.4.15.54]) by gabe.freedesktop.org (Postfix) with ESMTP id 2E27789E9B for ; Mon, 14 May 2018 13:20:57 +0000 (UTC) In-Reply-To: <87604gtuk7.fsf@anholt.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Eric Anholt Cc: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============0129832244== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="3gcw3tepxyrpusv3" Content-Disposition: inline --3gcw3tepxyrpusv3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Eric, On Tue, Apr 24, 2018 at 09:53:28AM -0700, Eric Anholt wrote: > Maxime Ripard writes: >=20 > > The vc4 HVS uses an internal RGB888 representation of the frames, and w= ill > > 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 disp= lay > > output in a reliable way. >=20 > 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) This was based on experiment, so I might have missed that case and you are probably right. I'll test with SCALER_CTL0_EXPAND_REPEAT and let you know :) Thanks! Maxime --=20 Maxime Ripard, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com --3gcw3tepxyrpusv3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE0VqZU19dR2zEVaqr0rTAlCFNr3QFAlr5jS0ACgkQ0rTAlCFN r3TeihAAkvKPZBS/GIPx8hQnj3KJufgf1wSTrhZ7pUvvPrafkhJRHrUg4BuOeXfe CmY0S3t7ySZw2FJ6g6eoMRXL0CRXRZ+cbmk01TZNd/FbFLUtjyb3ocgxIWs/MnyT 9xs/p8bP4kERjSO8jXsGsqZhUGEv7VTVBXuymZvGFJX+DMYtmBHwu9DwWgEtdWPQ iV0hG6rEDrDtiIo7oxH6VK9cbJGZDNSPZ5ry7OdDbUIbXw+mEy99sDuJCTGSy0kh DvsGmryiwumGpdA/QgetLsyzkQlTg8QGnBfDcEK1RuyBgYlZJbrzPmnX9PZ+pArb BrxD5enpUIpxQZB1YUm+S1hLL9k34N8LGvcHMS+mK0UiG03DTwSNGYkjauugsjrP EGA5q45L8lATo60XOzspcrx6MvyTZAoS3CQ3IEcol3RFPyHbYUJsSTfeiU6Mcve/ yE0C6QP9911tZfZXtjicWMmgrYBgUT5mv+OoWSnkWmGrKkIlDNysYCSZzRwzFOis 8oZa59O/DEyiduWXI7z4Om1yxC1iBlJNYjaHIt2rC4KfBAqRPy+Kqm9HO7FOmcFX 01DCczW04Tj7WTbeo2eHcHFmzk/mt64aQshhg0WPcLsJdxffGurwbhgZWg1E+6Ww CUiKmAjmSzkzZRcu/Avb3sf4NdTlUTnS4zvXb3lcXijQ9SJI7Vw= =jqLG -----END PGP SIGNATURE----- --3gcw3tepxyrpusv3-- --===============0129832244== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVsCg== --===============0129832244==--