From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kay Sievers Date: Sat, 26 Feb 2005 18:28:10 +0000 Subject: Re: event sequencing Message-Id: <1109442490.7400.91.camel@localhost.localdomain> List-Id: References: <9e473391050225081838f673c7@mail.gmail.com> In-Reply-To: <9e473391050225081838f673c7@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org On Sat, 2005-02-26 at 12:34 -0500, Jon Smirl wrote: >On Sat, 26 Feb 2005 14:11:08 +0100, Kay Sievers wrote: >> Stuff like HAL heavily depends on that as it needs to get the initial >> state of all devices at startup to present this to applications. But if >> there is any other way to get that without sysfs, it would work too, >> sure. > >I do have somewhat of a race issue. > >1) receive hardware interrupt of monitor change >2) empty the list of valid modes in sysfs >3) generate hotplug event to run userspace helper >4) userspace helper sets in new mode list >5) driver generates HAL event > >X could have picked a mode from the modelist before #1 >Then tried to set it between #1 and #4 >In this case X will get an error about invalid mode >That should cause a popup that tells the user to try again >while that popup is up the HAL event occurs indicating a new mode list >is available >This needs to be sorted out so that the contents of the mode selection >dialog update Yeah, this happens with other devices too and I don't see it as a big problem as long as is fails and the caller get an error back. >There need to be two events: >MODELIST_CHANGE >MODE_CHANGE > >MODE_CHANGE occurs if you are in an xterm and set a new mode via the >command line. X needs to know in order to fix the display. Are the list and the current state available as device attributes in sysfs? So you may just send a KOBJ_CHANGE event for that specific attributes with the kobject_uevent() which can have an attribute passed down which is appended to the devpath of the device. Kay ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_ide95&alloc_id396&op=click _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel