Op 10-11-17 om 14:24 schreef Daniel Vetter: > On Fri, Nov 10, 2017 at 02:13:39PM +0100, Daniel Vetter wrote: >> On Fri, Nov 10, 2017 at 12:34:58PM +0100, Maarten Lankhorst wrote: >>> Lock the bare minimum, instead of the entire world, and >>> use interruptible locking because we can. >>> >>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> >>> --- >>> drivers/gpu/drm/i915/i915_debugfs.c | 40 +++++++++++++++++++++++++++++-------- >>> 1 file changed, 32 insertions(+), 8 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c >>> index 39883cd915db..7e8f40eb970d 100644 >>> --- a/drivers/gpu/drm/i915/i915_debugfs.c >>> +++ b/drivers/gpu/drm/i915/i915_debugfs.c >>> @@ -2736,39 +2736,63 @@ static int i915_sink_crc(struct seq_file *m, void *data) >>> struct intel_connector *connector; >>> struct drm_connector_list_iter conn_iter; >>> struct intel_dp *intel_dp = NULL; >>> + struct drm_modeset_acquire_ctx ctx; >>> int ret; >>> u8 crc[6]; >>> >>> - drm_modeset_lock_all(dev); >>> + drm_modeset_acquire_init(&ctx, DRM_MODESET_ACQUIRE_INTERRUPTIBLE); >>> + >>> drm_connector_list_iter_begin(dev, &conn_iter); >> I kinda expect this funny locking nesting to upset lockdep, I think we >> have a bunch of places where we nest list_iter and modeset locks >> differently. >> >> I think the correct nesting is list_iter entirely within the ww_mutex >> stuff, which means you'd need to terminate the loop (and remember the >> connector), then after list_iter_end do the ww_mutex dance. Of course >> that's all assuming CI shows I'm right (hopefully it does since we no >> longer reboot, in the past finding these took a few runs until you had the >> right test combination to trigger this stuff). >> >> Even if we don't yet have such a case I'd really prefer that list_iter >> isn't nested between the acquire_ctx and modeset ww_mutex lockdep >> contexts. > Correction, this exact locking pattern already exists in > drm_atomic_add_affected_connectors, changing to what I suggested would > actually upset lockdep. Hence > > Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> Thanks, pushed up to here, would be nice if 7/11 would get a r-b too. No IPS related changes there yet, just the preparations. :) _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
