From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH 08/22] drm/tegra: dc: Drop the reset asserts to workaround a bug Date: Tue, 13 Jun 2017 15:45:46 +0200 Message-ID: <20170613134546.GH16758@ulmo.fritz.box> References: <35e1ef44da98701b2c507c31ecc0812530303d2d.1495498184.git.digetx@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="CNfT9TXqV7nd4cfk" Return-path: Content-Disposition: inline In-Reply-To: <35e1ef44da98701b2c507c31ecc0812530303d2d.1495498184.git.digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Dmitry Osipenko Cc: Mikko Perttunen , linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, DRI Development , Erik Faye-Lund List-Id: linux-tegra@vger.kernel.org --CNfT9TXqV7nd4cfk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 23, 2017 at 03:14:23AM +0300, Dmitry Osipenko wrote: > Commit 33a8eb8 ("Implement runtime PM") introduced HW reset control. It > causes a hang on Tegra20 if both display controllers are utilized (RGB > panel and HDMI). The TRM suggests that each display controller has its own > reset control, apparently it is not correct. Let's remove the interaction > with the resets for now as a workaround. >=20 > Fixes: 33a8eb8d40ee ("drm/tegra: dc: Implement runtime PM") > Signed-off-by: Dmitry Osipenko > --- > drivers/gpu/drm/tegra/dc.c | 15 --------------- > 1 file changed, 15 deletions(-) Do you mind if I parameterize this to restrict omission of the assert and deassert to Tegra20? I'm fairly sure that these resets are important on later chips in order to properly reset the display controllers. My proposal would be to add a field to struct tegra_dc_soc_info (maybe =2Ebroken_reset) that will be set only on Tegra20 to still allow the DC to be reset on later generations. Thierry --CNfT9TXqV7nd4cfk Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlk/7IoACgkQ3SOs138+ s6EaNg/+MU7/9PgCkqgh57OzI9bmDZlqt6JiN51dEVpvbpBXgXIVNR5CghC5n8+n uXijjPSmKgVRwTslEbW3DGN67TqOKGKNTuf0ya/OoGcN8U0jw1RsVMfi7NPankXm 9w4CcHI70ubwZ3oMERpstyo/WZEX7XX5BrhrIlsO0eymEeR3VDTVpToP43oGHQQ2 lm+qIR8yU4C6NCsLDkRPEFfzCNgy6lwgmx1vMmnAwHnDjCvtk7q/le2HFvX5KKxU XObhoHKyq6IZ/BE6sonBu5JU9T0w3mbFrY2ZAZBEz+CrRvnUC7sB2/j5NU3A32BI hUEzMHOkJKRC7K4w2FniAd7xWqMcbwsfkM3aCy40BiCGzyDyE0QCRicHpef6u7Ba csSDVMA1f3+x9D95zBwLYl2EO/v9ZQS/uPRrGeEhehuweEcM0BBA/VCh7bTCFtWy KLhXfNSsIUCyO3kIiohkrHu1H3tLyB/711KUaRXDErOyh5XTHbiAFBYFuUA0N9d5 9uLQGYoZvM5khcCL4FZCuN3xlEjaTJ5+neVAYZCI2spRCIw+xG3D3Uu76u03+4hk NON+cq22YjmTjxhMpZOsPgaL0/WWHy9f5ietvTJrEgrdCUoDC226D6FhOLKGM9x6 pHULySoDO0wm8RRLsqxNRCSeBs6LZ0x8rImI9DKw/8Rux3vlCsk= =zI1z -----END PGP SIGNATURE----- --CNfT9TXqV7nd4cfk--