From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomi Valkeinen Subject: Re: [PATCH v4 14/22] drm: omapdrm: Keep vblank interrupt enabled while CRTC is active Date: Thu, 15 Dec 2016 16:56:15 +0200 Message-ID: <87f5c29f-e4f2-ef96-10cd-e7d3e04fb04d@ti.com> References: <1481675266-24598-1-git-send-email-laurent.pinchart@ideasonboard.com> <1481675266-24598-15-git-send-email-laurent.pinchart@ideasonboard.com> <5fd3ff5e-e9e9-85c3-d9f2-b16d3524a677@ti.com> <2580087.D9jCYKYxOH@avalon> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0666715492==" Return-path: Received: from lelnx194.ext.ti.com (lelnx194.ext.ti.com [198.47.27.80]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6B9A86E9E4 for ; Thu, 15 Dec 2016 14:56:21 +0000 (UTC) In-Reply-To: <2580087.D9jCYKYxOH@avalon> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Laurent Pinchart Cc: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org --===============0666715492== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="RePFr3LU18BlLsxCGW4L6Asoqk8bRd8e8" --RePFr3LU18BlLsxCGW4L6Asoqk8bRd8e8 Content-Type: multipart/mixed; boundary="n3otEBDAA376BBX3rv7ClwTRhNiigqNIK"; protected-headers="v1" From: Tomi Valkeinen To: Laurent Pinchart Cc: dri-devel@lists.freedesktop.org Message-ID: <87f5c29f-e4f2-ef96-10cd-e7d3e04fb04d@ti.com> Subject: Re: [PATCH v4 14/22] drm: omapdrm: Keep vblank interrupt enabled while CRTC is active References: <1481675266-24598-1-git-send-email-laurent.pinchart@ideasonboard.com> <1481675266-24598-15-git-send-email-laurent.pinchart@ideasonboard.com> <5fd3ff5e-e9e9-85c3-d9f2-b16d3524a677@ti.com> <2580087.D9jCYKYxOH@avalon> In-Reply-To: <2580087.D9jCYKYxOH@avalon> --n3otEBDAA376BBX3rv7ClwTRhNiigqNIK Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 15/12/16 16:51, Laurent Pinchart wrote: >>> + WARN_ON(drm_crtc_vblank_get(crtc) !=3D 0); >> >> I don't like this style very much. I think WARN()s should be without >> side effects. >> >> Also, WARN only gives benefit when we don't know what the call stack i= s. >> Afaik, there's only one way omap_crtc_atomic_flush can be called, so >> it's just extra spam and dev_err or dev_warn should be enough. >=20 > I've used it because the equivalent statements testing omap_crtc- >> vblank_irq.registered used WARN_ON() too. WARN_ON() is also a bit more= vocal,=20 > it really gets the point across. As the function really should not retu= rn an=20 > error unless in case of a driver bug, I don't think it will generate an= y spam.=20 > I don't care too much though, I can replace it with a dev_err() if you = insist. I don't mind using WARN_ON() that much. But that's the comment I've received a few times, so I shared it =3D). What I do care is the side effect inside WARN_ON. At least for me it's quite easy to miss that it's actually having a side effect, as I expect WARN_ON() to be just a check, like assert(). So when reading the code, I skip the WARN_ONs. Tomi --n3otEBDAA376BBX3rv7ClwTRhNiigqNIK-- --RePFr3LU18BlLsxCGW4L6Asoqk8bRd8e8 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJYUq8PAAoJEPo9qoy8lh71/UUQAJwRXZsdGI3+qkX8bOJQKtnf 0maJw3htcLdBiedMy1bDhJ0oKPGhJGNVevvaG3Qh6rXUssHe0NfQEIbITUtXDuL1 wd0x4mFcQrUlf6ChT6l9ngEst/+SAF1j0gLODYkhW3q3daYEnaU9qxNpjAU+EFHG ZDAaRNSMAaLJU0mt8B8joyTlfNPSkYj67rldjg75FUmATrI9C8/sN7Cz3rMV84Zs LuiUgvjyDDfE00jWgNMgMoFNTYlMDNHvQ+4x3b+UNvOWD/wPU/SQJbfbBknI+t15 vtBvf/2PpNSLB+vlm6yNSCMjwFg+mLNVXm8tQf1GmD1WLbhOD9MJ3DNyNGz6J9GM TIV/2OUlpfcAtiK5gnlyU25ZTHSxqpndfKojugrDzQ8hYFxm5FmMwwmTplNreynX Lce9ZPSbU+GoxrbL/376R4+bUAtMlYU3dcc+MbxEiA0Jv5UnuAngHNBEXiUDV3A+ M+2WQ44z6DGH4Wq2FZyqt5a7hPaE4eauW/J731yoGLhbt+TSOLidVJWADWHJa0Rp G7pIjZB8WNPlENWv0prmW9HYlm2ovtLB5S8F295TZ2Q1KOxcaRiDRn9S0ms/RDPO irr5hGGblmyGxsO6wXyz3x0d8Oe8AY/cypJ6ZgYMWKr5bhi3Uj3Y8vHKXH+xOrwe cIa4oz5C84PmdiZ6u2ac =sk0t -----END PGP SIGNATURE----- --RePFr3LU18BlLsxCGW4L6Asoqk8bRd8e8-- --===============0666715492== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KZHJpLWRldmVs IG1haWxpbmcgbGlzdApkcmktZGV2ZWxAbGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlz dHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlzdGluZm8vZHJpLWRldmVsCg== --===============0666715492==--