From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Garrett Date: Thu, 21 Nov 2013 14:33:26 +0000 Subject: Re: [PATCH] video: backlight: Remove backlight sysfs uevent Message-Id: <20131121143326.GA19773@srcf.ucam.org> List-Id: References: <20131111235700.GA29987@july> <002901cedf3c$a7e77a00$f7b66e00$%han@samsung.com> <20131112005628.GA2914@khazad-dum.debian.net> <1384990859.20536.4.camel@x230> <20131121114332.GA23710@khazad-dum.debian.net> In-Reply-To: <20131121114332.GA23710@khazad-dum.debian.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Henrique de Moraes Holschuh Cc: Jingoo Han , 'Kyungmin Park' , 'Henrique de Moraes Holschuh' , linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, kay@vrfy.org, 'Richard Purdie' , ibm-acpi-devel@lists.sourceforge.net, platform-driver-x86@vger.kernel.org On Thu, Nov 21, 2013 at 09:43:32AM -0200, Henrique de Moraes Holschuh wrote: > With this patchset applied, as far as I can tell anything that used to be > uevent-driven by the backlight class will break: when a process changes the > backlight using sysfs, other processes will not be notified of the change > anymore. This patchset seems to break backlight uevent support in such a > way that basically renders the entire thing useless and you might as well > just remove uevent support entirely. The uevent support was initially added to handle systems where pressing a hotkey generates an event (good) but the firmware automatically changes the brightness (bad). I have absolutely no idea why I added BACKLIGHT_UPDATE_SYSFS - BACKLIGHT_UPDATE_HOTKEY solves the problem I was trying to solve. I'm not aware of any userspace that relies on BACKLIGHT_UPDATE_SYSFS. -- Matthew Garrett | mjg59@srcf.ucam.org