On Mon, Mar 14, 2016 at 04:59:20PM +0200, Imre Deak wrote: > Add support for forcing an error at selected places in the driver. As an > example add 4 options to fail during driver loading. > > Requested by Chris. > > v2: > - Add fault point for modeset initialization > - Print debug message when injecting an error > v3: > - Rename inject_fault to inject_load_failure, rename the related macros > and helper accordingly (Chris) > > CC: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> > --- > > [This depends on > https://lists.freedesktop.org/archives/intel-gfx/2016-March/089597.html] > > drivers/gpu/drm/i915/i915_dma.c | 12 ++++++++++++ > drivers/gpu/drm/i915/i915_drv.h | 16 ++++++++++++++++ > drivers/gpu/drm/i915/i915_params.c | 5 +++++ > drivers/gpu/drm/i915/i915_params.h | 1 + > 4 files changed, 34 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c > index a5121cd..7490307 100644 > --- a/drivers/gpu/drm/i915/i915_dma.c > +++ b/drivers/gpu/drm/i915/i915_dma.c > @@ -370,6 +370,9 @@ static int i915_load_modeset_init(struct drm_device *dev) > struct drm_i915_private *dev_priv = dev->dev_private; > int ret; > > + if (i915_inject_load_failure(I915_FAIL_INIT_MODESET)) > + return -ENODEV; > + > ret = intel_bios_init(dev_priv); > if (ret) > DRM_INFO("failed to find VBIOS tables\n"); > @@ -950,6 +953,9 @@ static int i915_driver_init_early(struct drm_i915_private *dev_priv, > struct intel_device_info *device_info; > int ret = 0; > > + if (i915_inject_load_failure(I915_FAIL_INIT_EARLY)) > + return -ENODEV; > + > dev_priv->dev = dev; > > /* Setup the write-once "constant" device info */ > @@ -1064,6 +1070,9 @@ static int i915_driver_init_mmio(struct drm_i915_private *dev_priv) > struct drm_device *dev = dev_priv->dev; > int ret; > > + if (i915_inject_load_failure(I915_FAIL_INIT_MMIO)) > + return -ENODEV; > + > if (i915_get_bridge_dev(dev)) > return -EIO; Ok, thought a bit more about this, and if we really want to check all the load failure paths then this will become extremely verbose. Since we'd need to have a bitflag for every return -EFAIL. So maybe another look at lib/fault-inject.c is warranted, plus then some macro magic that we could to wrap _all_ the checks in our load code like this: if (i915_load_failure(i915_get_bridge_dev(dev))) return -EIO; i915_load_failure ofc needs to fail if it's argument is false, but it could also increment a counter every time it's called and then use that counter to inquire the fault injection framework with should_fail(i915_load_failures, counter). Abusing a counter for the size would allow us to easily restrict fault injection to a certain range of faults. We could also expose the final value of that counter in debugfs, so that the igt can tune itself. Anyway, this is kinda a big plan, but the part I think we should ponder is how to make the fault injection less noise and intrusive. A macro to wrap existing checks seems like a good idea. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
