Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752516AbaBJKkj (ORCPT ); Mon, 10 Feb 2014 05:40:39 -0500 Received: from mail-ee0-f53.google.com ([74.125.83.53]:42272 "EHLO mail-ee0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751819AbaBJKkh (ORCPT ); Mon, 10 Feb 2014 05:40:37 -0500 Date: Mon, 10 Feb 2014 11:40:34 +0100 From: Thierry Reding To: Linus Walleij Cc: Jingoo Han , Arnd Bergmann , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pwm@vger.kernel.org Subject: Re: [PATCH] backlight: add PWM dependencies Message-ID: <20140210104032.GB20143@ulmo.nvidia.com> References: <1391518634-6472-1-git-send-email-linus.walleij@linaro.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="O5XBE6gyVG5Rl6Rj" Content-Disposition: inline In-Reply-To: <1391518634-6472-1-git-send-email-linus.walleij@linaro.org> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --O5XBE6gyVG5Rl6Rj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Feb 04, 2014 at 01:57:14PM +0100, Linus Walleij wrote: > In some compilations the LM3630A and LP855X backlight drivers > fail like this: >=20 > drivers/built-in.o: In function `lm3630a_pwm_ctrl': > drivers/video/backlight/lm3630a_bl.c:168: undefined reference to `pwm_con= fig' > drivers/video/backlight/lm3630a_bl.c:172: undefined reference to `pwm_dis= able' > drivers/video/backlight/lm3630a_bl.c:170: undefined reference to `pwm_ena= ble' > drivers/built-in.o: In function `lp855x_pwm_ctrl': > drivers/video/backlight/lp855x_bl.c:249: undefined reference to `pwm_conf= ig' > drivers/video/backlight/lp855x_bl.c:253: undefined reference to `pwm_disa= ble' > drivers/video/backlight/lp855x_bl.c:251: undefined reference to `pwm_enab= le' >=20 > This is because both drivers depend on the PWM framework, so > add this dependency to their Kconfig entries. >=20 > Signed-off-by: Linus Walleij > --- > drivers/video/backlight/Kconfig | 2 ++ > 1 file changed, 2 insertions(+) Hi Linus, it seems like at least BACKLIGHT_LP8788 is missing a corresponding dependency as well. I have applied Sascha's patch to remove the obsolete HAVE_PWM symbol, and this will fix at least the build issues. However it will also cause the driver to fail at runtime because the pwm_*() functions won't work. So I wonder if we should still apply this patch to make it clear that PWM support is necessary to make the driver work. I guess the point is somewhat moot because even if we had PWM enabled it could still happen that no PWM driver is enabled to provide a PWM device... I guess it's equally justifiable to leave that up to the defconfig. Should we just drop this patch? Cc'ing Arnd who's commented on Jingoo's alternate proposal. Thierry --O5XBE6gyVG5Rl6Rj Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJS+KygAAoJEN0jrNd/PrOhfbcP/3oRQku7bR3KbIgDBe50UF99 h6V/ToVfLD7tdhyHNz0sVLLJAeOUdCCRw2ABrDAQu27c1OH0ss38isg2866lZD4Z 9XMSmWkLYocmXjXyKAOgRdlSIJ9CDM8QWsH6V3ciBt7vKjt0e+bV7UXysuZCc3MI IUcDm/VqxIXezK6MEpHmwRuTdUUiofiiTu+foYhsHTQtHvZ+zNoYTzn3iQBOcu04 3RkQWyf+N4MZ7mcTpK2o35/Zy9v6Z1i69J2vP9AxR3VxkdHHCJMfykPe0mtTzhUv 7qMhBS3vXPAdE0hIMzvQiaR2/N57RuEHVElWRUA/L0vnc5lAV9Kc1hUqegt4h3l7 oNzNnXQUIPIWKG7lqJHPPF6y7VyT0G2PKLsmyvmvD9IgugNY+Qgf4moeZm91veCZ L9u8YijOV3OxRKwB+BahshF20evdeM4FG8JnXRbSe1m1rKKo+TkiweCzLvOEcGKf /EAAH4bICc0grJ3d0aK+IbUrvlAto9djGyvIMqV1M+wU7Obc/dCPMomJh+/Pr7OF /QnDmiLy944LKR5ACYsIJnJeEZVtJvKFuKnCdXEQhyxS24LPtJdCfBuEPJNYAnXj hlYt9HuZdLDappgHcf8dB+PNky/6VrYSjhZM2g85ykHRCDuXecVwR5cZ5wIlvW8q 4+vAD7DCVRtUcuoCmts2 =71tB -----END PGP SIGNATURE----- --O5XBE6gyVG5Rl6Rj-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/