| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Sat, 17 Nov 2012 17:07:39 +1300 From: Tony Prisk <linux@...sktech.co.nz> To: Thierry Reding <thierry.reding@...onic-design.de> Cc: linux-kernel@...r.kernel.org, Arm Kernel Mailing List <linux-arm-kernel@...ts.infradead.org>, VT8500 Mailing List <vt8500-wm8505-linux-kernel@...glegroups.com> Subject: pwm_backlight/general pwm issue. Hi Thierry, Looking a little feedback regarding a problem introduced with the pwm patch I sent converting the vt8500 pwm driver to devicetree. One of the recommendations you made was to enable/disable the pwm clock in pwm_enable/pwm_disable, rather than at driver probe, to reduce power usage. Unfortunately, when the last pwm is disabled, the clock is disabled which prevents the pwm module from responding to register read/writes. This would be fine if pwm_enable was called before any other functions. The pwm_backlight driver calls pwm_config before pwm_enable, which doesn't work because the pwm module has been disabled. I can appreciate that no one wants to enable a pwm before it's configured so I don't think this is particularly a driver issue. My recommendation is the re-enable the previous behaviour which was to enable the clock during driver probe, and disable during driver unload. Looking for your thoughts (or anyone else that wants to chime in). Regards Tony Prisk -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists