On Sun, 2010-08-15 at 21:01 -0700, Linus Torvalds wrote: > On Sun, Aug 15, 2010 at 8:30 PM, Dave Airlie <airlied@xxxxxxxxxx> wrote: > > > > At least we should replace mdelay with msleep in those functions. > > How precise does the timing have to be? I think i2c is self-clocking, > so it's ok to see big skews? Becuase msleep() can be off by quite a > bit (mdelay can too, but it's _way_ more rare, and requires either a > preemptible kernel or serious interrupt activity). In this case it definitely doesn't matter, I expect msleep to be a much nicer to the system in general idea esp in routines we can all at runtime from userspace. > > > Can you get a boot with drm.debug=4? > > Sure. That results in a truncated dmesg (with a 128k buffer). The > thing seems to spew out something every ten seconds: > > ... > [ 232.610044] [drm:intel_sdvo_debug_write], SDVOB: W: 0B > (SDVO_CMD_GET_ATTACHED_DISPLAYS) > [ 232.624504] [drm:intel_sdvo_debug_response], SDVOB: R: 01 00 > (Success) > [ 232.624517] [drm:intel_sdvo_detect], SDVO response 1 0 > [ 232.624524] [drm:intel_sdvo_debug_write], SDVOB: W: 7A 01 > (SDVO_CMD_SET_CONTROL_BUS_SWITCH) > [ 242.672044] [drm:intel_sdvo_debug_write], SDVOB: W: 0B > (SDVO_CMD_GET_ATTACHED_DISPLAYS) > [ 242.686503] [drm:intel_sdvo_debug_response], SDVOB: R: 01 00 > (Success) > [ 242.686516] [drm:intel_sdvo_detect], SDVO response 1 0 > [ 242.686523] [drm:intel_sdvo_debug_write], SDVOB: W: 7A 01 > (SDVO_CMD_SET_CONTROL_BUS_SWITCH) > [ 252.750044] [drm:intel_sdvo_debug_write], SDVOB: W: 0B > (SDVO_CMD_GET_ATTACHED_DISPLAYS) > [ 252.764526] [drm:intel_sdvo_debug_response], SDVOB: R: 01 00 > (Success) > [ 252.764539] [drm:intel_sdvo_detect], SDVO response 1 0 > ... > > It looks like it takes about 15 ms each time. But 15 ms each 10s > doesn't seem to be enough to account for the load average. Maybe it > gets synchronized with the timer tick or something, causing the load > average to look artificially inflated (it also doesn't match up with > kworker using 1%+ CPU time). > > So maybe there is something else going on. Maybe the load average > thing comes from some interaction with the new workqueue thing. > > I'll send the whole dmesg to you in a private message, I don't think > we want 128kB of crud on lkml. > > > I wonder are we picking up a bad SDVO, the insane code retries 50 times > > with a hard loop delay. > > Well, I'm not seeing any failures, but maybe those don't get printed out? Oh wierd, so not where I thought it was, I expect then the SDVO HDMI detection is completely insane, intel_sdvo_hdmi_sink_detect looks to contain some really uninspiring code. Might be worth adding some debug in there to see if it sinks a lot of time. Dave. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
