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f4457ae71f
Reporting -EIO from i915_wait_request() has proven very troublematic over the years, with numerous hard-to-reproduce bugs cropping up in the corner case of where a reset occurs and the code wasn't expecting such an error. If the we reset the GPU or have detected a hang and wish to reset the GPU, the request is forcibly complete and the wait broken. Currently, we report either -EAGAIN or -EIO in order for the caller to retreat and restart the wait (if appropriate) after dropping and then reacquiring the struct_mutex (essential to allow the GPU reset to proceed). However, if we take the view that the request is complete (no further work will be done on it by the GPU because it is dead and soon to be reset), then we can proceed with the task at hand and then drop the struct_mutex allowing the reset to occur. This transfers the burden of checking whether it is safe to proceed to the caller, which in all but one instance it is safe - completely eliminating the source of all spurious -EIO. Of note, we only have two API entry points where we expect that userspace can observe an EIO. First is when submitting an execbuf, if the GPU is terminally wedged, then the operation cannot succeed and an -EIO is reported. Secondly, existing userspace uses the throttle ioctl to detect an already wedged GPU before starting using HW acceleration (or to confirm that the GPU is wedged after an error condition). So if the GPU is wedged when the user calls throttle, also report -EIO. v2: Split more carefully the change to i915_wait_request() and assorted ABI from the reset handling. v3: Add a couple of WARN_ON(EIO) to the interruptible modesetting code so that we don't start to leak EIO there in future (and break our hang resistant modesetting). Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-9-git-send-email-chris@chris-wilson.co.uk Link: http://patchwork.freedesktop.org/patch/msgid/1460565315-7748-1-git-send-email-chris@chris-wilson.co.uk |
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| amd | ||
| arm | ||
| armada | ||
| ast | ||
| atmel-hlcdc | ||
| bochs | ||
| bridge | ||
| cirrus | ||
| etnaviv | ||
| exynos | ||
| fsl-dcu | ||
| gma500 | ||
| i2c | ||
| i810 | ||
| i915 | ||
| imx | ||
| mga | ||
| mgag200 | ||
| msm | ||
| nouveau | ||
| omapdrm | ||
| panel | ||
| qxl | ||
| r128 | ||
| radeon | ||
| rcar-du | ||
| rockchip | ||
| savage | ||
| shmobile | ||
| sis | ||
| sti | ||
| tdfx | ||
| tegra | ||
| tilcdc | ||
| ttm | ||
| udl | ||
| vc4 | ||
| vgem | ||
| via | ||
| virtio | ||
| vmwgfx | ||
| ati_pcigart.c | ||
| drm_agpsupport.c | ||
| drm_atomic_helper.c | ||
| drm_atomic.c | ||
| drm_auth.c | ||
| drm_bridge.c | ||
| drm_bufs.c | ||
| drm_cache.c | ||
| drm_context.c | ||
| drm_crtc_helper.c | ||
| drm_crtc_internal.h | ||
| drm_crtc.c | ||
| drm_debugfs.c | ||
| drm_dma.c | ||
| drm_dp_aux_dev.c | ||
| drm_dp_helper.c | ||
| drm_dp_mst_topology.c | ||
| drm_drv.c | ||
| drm_edid_load.c | ||
| drm_edid.c | ||
| drm_encoder_slave.c | ||
| drm_fb_cma_helper.c | ||
| drm_fb_helper.c | ||
| drm_flip_work.c | ||
| drm_fops.c | ||
| drm_gem_cma_helper.c | ||
| drm_gem.c | ||
| drm_global.c | ||
| drm_hashtab.c | ||
| drm_info.c | ||
| drm_internal.h | ||
| drm_ioc32.c | ||
| drm_ioctl.c | ||
| drm_irq.c | ||
| drm_kms_helper_common.c | ||
| drm_legacy.h | ||
| drm_lock.c | ||
| drm_memory.c | ||
| drm_mipi_dsi.c | ||
| drm_mm.c | ||
| drm_modes.c | ||
| drm_modeset_lock.c | ||
| drm_of.c | ||
| drm_panel.c | ||
| drm_pci.c | ||
| drm_plane_helper.c | ||
| drm_platform.c | ||
| drm_prime.c | ||
| drm_probe_helper.c | ||
| drm_rect.c | ||
| drm_scatter.c | ||
| drm_sysfs.c | ||
| drm_trace_points.c | ||
| drm_trace.h | ||
| drm_vm.c | ||
| drm_vma_manager.c | ||
| Kconfig | ||
| Makefile | ||