Attachment 107840 Details for Bug 83484 – Possible fix

[patch] Possible fix

0001-drm-i915-call-drm_vblank_cleanup-earlier-at-unload.patch (text/plain), 3.45 KB, created by Paulo Zanoni on 2014-10-14 21:18:58 UTC

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Creator: Paulo Zanoni

Created: 2014-10-14 21:18:58 UTC

Size: 3.45 KB

patch

obsolete

>From 11fee7afbdcfab3830e393c4f871c146160c73ee Mon Sep 17 00:00:00 2001
>From: Paulo Zanoni <paulo.r.zanoni@intel.com>
>Date: Tue, 14 Oct 2014 18:11:35 -0300
>Subject: [PATCH] drm/i915: call drm_vblank_cleanup() earlier at unload
>
>In its current place, it just segfaults while trying to access the
>CRTC structures:
>
>[ 9132.421681] Call Trace:
>[ 9132.421707]  [<ffffffffa01130d8>] i915_get_crtc_scanoutpos+0x1e8/0x220 [i915]
>[ 9132.421727]  [<ffffffffa001da34>] drm_calc_vbltimestamp_from_scanoutpos+0x94/0x330 [drm]
>[ 9132.421744]  [<ffffffffa001d240>] ?vblank_disable_and_save+0x40/0x1e0 [drm]
>[ 9132.421769]  [<ffffffffa0114328>] i915_get_vblank_timestamp+0x68/0xb0 [i915]
>[ 9132.421786]  [<ffffffffa001d094>] drm_get_last_vbltimestamp+0x44/0x80 [drm]
>[ 9132.421801]  [<ffffffffa001d3a6>] vblank_disable_and_save+0x1a6/0x1e0 [drm]
>[ 9132.421817]  [<ffffffffa001eac1>] drm_vblank_cleanup+0x61/0xa0 [drm]
>[ 9132.421849]  [<ffffffffa0177a5e>] i915_driver_unload+0xde/0x290 [i915]
>[ 9132.421867]  [<ffffffffa0020264>] drm_dev_unregister+0x24/0xb0 [drm]
>[ 9132.421884]  [<ffffffffa002090e>] drm_put_dev+0x1e/0x70 [drm]
>[ 9132.421901]  [<ffffffffa00e01e0>] i915_pci_remove+0x10/0x20 [i915]
>[ 9132.421910]  [<ffffffff81347556>] pci_device_remove+0x36/0xb0
>[ 9132.421920]  [<ffffffff8140084a>] __device_release_driver+0x7a/0xf0
>[ 9132.421928]  [<ffffffff81400fc8>] driver_detach+0xb8/0xc0
>[ 9132.421936]  [<ffffffff8140054a>] bus_remove_driver+0x4a/0xb0
>[ 9132.421944]  [<ffffffff81401717>] driver_unregister+0x27/0x50
>[ 9132.421953]  [<ffffffff81346f65>] pci_unregister_driver+0x25/0x70
>[ 9132.421971]  [<ffffffffa00229c8>] drm_pci_exit+0x78/0xa0 [drm]
>[ 9132.422000]  [<ffffffffa017a6d2>] i915_exit+0x20/0x94e [i915]
>[ 9132.422009]  [<ffffffff810fb9dc>] SyS_delete_module+0x13c/0x1f0
>[ 9132.422019]  [<ffffffff8131c5fb>] ?
>trace_hardirqs_on_thunk+0x3a/0x3f
>[ 9132.422028]  [<ffffffff816f7792>] system_call_fastpath+0x16/0x1b
>
>This means it has to be before intel_modeset_cleanup, which cleans the
>CRTC structures. But if we move it to before intel_fbdev_fini(), we
>get WARNs because intel_fbdev_fini() still tries to use the vblanks,
>so the only acceptable point for drm_vblank_cleanup() seems to be this
>place.
>
>Related commit:
>
>    commit cbb47d179fb345c579cd8cd884693903fceed26a
>    Author: Chris Wilson <chris@chris-wilson.co.uk>
>    Date:   Mon Sep 23 17:33:20 2013 -0300
>        drm/i915: Add some missing steps to i915_driver_load error path
>
>Testsuite: igt/drv_module_reload
>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=77511
>Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83484
>Cc: Chris Wilson <chris@chris-wilson.co.uk>
>Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
>---
> drivers/gpu/drm/i915/i915_dma.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
>index 85d14e1..1b39807 100644
>--- a/drivers/gpu/drm/i915/i915_dma.c
>+++ b/drivers/gpu/drm/i915/i915_dma.c
>@@ -1853,8 +1853,12 @@ int i915_driver_unload(struct drm_device *dev)
> 
> 	acpi_video_unregister();
> 
>-	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
>+	if (drm_core_check_feature(dev, DRIVER_MODESET))
> 		intel_fbdev_fini(dev);
>+
>+	drm_vblank_cleanup(dev);
>+
>+	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
> 		intel_modeset_cleanup(dev);
> 
> 		/*
>@@ -1895,8 +1899,6 @@ int i915_driver_unload(struct drm_device *dev)
> 			i915_free_hws(dev);
> 	}
> 
>-	drm_vblank_cleanup(dev);
>-
> 	intel_teardown_gmbus(dev);
> 	intel_teardown_mchbar(dev);
> 
>-- 
>2.1.1
>

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