On Fri, Dec 4, 2009 at 5:58 PM, Luc Verhaegen <l...@skynet.be> wrote: > On Fri, Dec 04, 2009 at 05:18:21PM -0500, Alex Deucher wrote: >> This set of patches adds interrupt driven HPD (Hot Plug Detect) >> support to r1xx-r7xx radeons. Assuming the HPD pin is wired up >> correctly, the driver will generate uevents for digital monitor >> connect and disconnect and will retrain DP monitors automatically. >> The pin sense functionality can also be used to differentiate between >> multiple monitors connected to the same encoder or sharing a ddc line, >> however, that has not been hooked up yet. >> >> Alex > > Wasn't HPD evil for some reason a few years back? I remember you, > bridgie and davey throwing tons of crap at radeonhd for using HPD, and > here you are hooking it up to the same r5xx hardware, even though you > seem to prefer to name the hooks rs600. > > What is so different now then?
Nothing is different. You wanted to use them directly for monitor detection, but prior to r6xx, they shouldn't be used as the sole means of detecting if a monitor is connected or not since they were not always wired up properly by the oems. That's why radeonhd won't fail to start up for some people and then you'd make them run conntest and sort out the hpd routing. As I said back then, you shouldn't use the hpd pins directly for detection on pre-r6xx cards. The drm doesn't use them directly for monitor detection, it still uses the edid, as I advised you back then. The drm uses them to generate interrupts on hpd connect/disconnect events. The drm then issues a uevent that userspace can listen for and act on. Other than displayport (which is r6xx+ only), it doesn't matter if the hpd routing is correct or not since all we use it for is to generate an interrupt that something has changed. Userspace can then use the event to probe the connectors, or whatever. Alex ------------------------------------------------------------------------------ Join us December 9, 2009 for the Red Hat Virtual Experience, a free event focused on virtualization and cloud computing. Attend in-depth sessions from your desk. Your couch. Anywhere. http://p.sf.net/sfu/redhat-sfdev2dev -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
