From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH V6 0/8] drm/exynos: few patches to enhance bridge chip support Date: Wed, 30 Jul 2014 11:40:54 +0200 Message-ID: <20140730094053.GB29590@ulmo> References: <1406316130-4744-1-git-send-email-ajaykumar.rs@samsung.com> <53D5435B.8030305@suse.de> <53D783CC.2080108@suse.de> <20140729113645.GB21732@ulmo.nvidia.com> <53D78891.4080703@suse.de> <20140729114736.GB26346@ulmo.nvidia.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1127332615==" Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Ajay kumar Cc: Doug Anderson , "devicetree@vger.kernel.org" , "linux-samsung-soc@vger.kernel.org" , Sean Paul , Daniel Vetter , sunil joshi , "dri-devel@lists.freedesktop.org" , Ajay Kumar , Javier Martinez Canillas , Prashanth G , Andreas =?utf-8?Q?F=C3=A4rber?= List-Id: devicetree@vger.kernel.org --===============1127332615== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="tjCHc7DPkfUGtrlw" Content-Disposition: inline --tjCHc7DPkfUGtrlw Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jul 30, 2014 at 11:54:00AM +0530, Ajay kumar wrote: > Hi Thierry, >=20 > On Tue, Jul 29, 2014 at 5:17 PM, Thierry Reding > wrote: > > On Tue, Jul 29, 2014 at 01:42:09PM +0200, Andreas F=C3=A4rber wrote: > >> Am 29.07.2014 13:36, schrieb Thierry Reding: > >> > On Tue, Jul 29, 2014 at 01:21:48PM +0200, Andreas F=C3=A4rber wrote: > >> >> Hi Ajay, > >> >> > >> >> Am 28.07.2014 08:13, schrieb Ajay kumar: > >> >>> On 7/27/14, Andreas F=C3=A4rber wrote: > >> >>>> Am 25.07.2014 21:22, schrieb Ajay Kumar: > >> >>>>> This series is based on exynos-drm-next branch of Inki Dae's tre= e at: > >> >>>>> git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos= =2Egit > >> >>>>> > >> >>>>> I have tested this after adding few DT changes for exynos5250-sn= ow, > >> >>>>> exynos5420-peach-pit and exynos5800-peach-pi boards. > >> >>>> > >> >>>> I'm trying to test this with a modified exynos5250-spring DT > >> [...] > >> >> Unfortunately the most I got on Spring with attached DT was a blank > >> >> screen with a white horizontal line in the middle. > >> >> > >> >> Do I need to specify a specific panel model for Spring? > >> [...] > >> >> From 9172a26a8f0d0f0d170bd27e1c150ad204d8086a Mon Sep 17 00:00:00 2= 001 > >> >> From: =3D?UTF-8?q?Andreas=3D20F=3DC3=3DA4rber?=3D > >> >> Date: Sun, 27 Jul 2014 21:58:06 +0200 > >> >> Subject: [PATCH] ARM: dts: exynos5250: Add eDP/LVDS bridge to Spring > >> >> MIME-Version: 1.0 > >> >> Content-Type: text/plain; charset=3DUTF-8 > >> >> Content-Transfer-Encoding: 8bit > >> >> > >> >> Signed-off-by: Ajay Kumar > >> >> [AF: Redone for v6] > >> >> Signed-off-by: Andreas F??rber > >> >> --- > >> >> arch/arm/boot/dts/exynos5250-spring.dts | 32 +++++++++++++++++++++= ++++++++++- > >> >> 1 file changed, 31 insertions(+), 1 deletion(-) > >> >> > >> >> diff --git a/arch/arm/boot/dts/exynos5250-spring.dts b/arch/arm/boo= t/dts/exynos5250-spring.dts > >> >> index 687dfab86bc8..517b1ff2bfdf 100644 > >> >> --- a/arch/arm/boot/dts/exynos5250-spring.dts > >> >> +++ b/arch/arm/boot/dts/exynos5250-spring.dts > >> >> @@ -64,10 +64,14 @@ > >> >> vdd_pll-supply =3D <&s5m_ldo8_reg>; > >> >> }; > >> >> > >> >> + panel: panel { > >> >> + compatible =3D "simple-panel"; > >> >> + }; > >> > > >> > You can't do this. "simple-panel" isn't a valid panel model. It shou= ld > >> > probably be removed from the platform_of_match table in the driver. > >> > >> Okay, that means the Snow DT is wrong, too: > >> https://patchwork.kernel.org/patch/4625441/ > >> > >> And the others specify it as fallback: > >> https://patchwork.kernel.org/patch/4625461/ > >> https://patchwork.kernel.org/patch/4625451/ > > > > A quick grep shows that many (all?) devices that use DRM panels provide > > simple-panel as fallback. That's probably fine as long as they also do > > provide the specific model. But given that simple-panel does not have a > > mode or physical size, I don't think even that makes sense. > On snow, the bridge chip provides the display mode instead of the panel. > That is why display was working for me. Okay, I suppose under some circumstances that might make sense. Although it's still always the panel that dictates the display timings, so the panel node needs to have a panel model specific compatible value with a matching entry in the panel-simple driver so that it can even be used in setups without a bridge. One other thing: how does the bridge know which mode to drive? I suspect that it can drive more than one mode? Can it freely be configured or does it have a predefined set of modes? If the latter, then according to what you said above there needs to be a way to configure the bridge (via DT?) so that it reports the mode matching the panel. I wonder if that should be handled completely in code, so that for example a bridge has a panel attached it can use the panel's .get_modes() and select a matching mode among the set that it supports. Thierry --tjCHc7DPkfUGtrlw Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBAgAGBQJT2L2lAAoJEN0jrNd/PrOh1IcP/3X9wC59aJVO0OFx/YXWJdPR +Xjq/QqZGT32GKOja2q4TLvQgXh/kjtw9BRufXotb4GtdpdvKiBtm11oqU3OQrJU orZooJp987UnF9DAPep93JofWmLEuFI8EPApU7R9pxvtimcmU2SsKCW0QNaB0rYW IZ/g5rsxiMNegUq1Xd382ekgYAj9ak4u6zruZPSHZeEU/0za7IApFYqMwyAruJFd NYZ5kcvcWSzp1I8D5HPsFA81CSSA2urUtqVArnVotk5vS9YGIP4uXRsr9Nq+uWVD bIhDDoqJTflF99KvdlF9jEa1fz++8Ge3xFX3KqZYfATzUAxwyzXdsGHzRVDu8Ba+ ablU1j6B2CzHA7oZxRERSS5BNcnsh64QecSGR70+rXPBmCwL4p/eosrObCcB1axg NCctKCtY3m9DdTarx4vP9+ksFfsj4CrdptXg1sNUKkGqNY7P1Ssi4FwnagYsmVRP AWWtAYtEDJtQ9SPi2duSI7Hzoi939UE6ZpqrOBCD+sLDUs3p7Tehf5u4WKnpBN+N wIIIYTAwNk1VdflyZUVSpJUU3tvu/iZmAJ4CpYeLfReQYc+0veNh3hy2u3EFLCUv kZQMbH5WqXU8TpU7SXDQVOHOsJJtD4k7tdftZy+lSvTId98Gw2xrrE0IJp+qt5x/ Avv2Vpm8o3qUM+nszkuq =+4V+ -----END PGP SIGNATURE----- --tjCHc7DPkfUGtrlw-- --===============1127332615== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel --===============1127332615==--