On Wed, Feb 15, 2017 at 04:12:04PM +0200, Ville Syrjälä wrote:
> On Wed, Feb 15, 2017 at 01:15:47PM +0000, Chris Wilson wrote:
> > In order to prevent accessing the hpd registers outside of the display
> > power wells, we should refrain from writing to the registers before the
> > display interrupts are enabled.
> >
> > [ 4.740136] WARNING: CPU: 1 PID: 221 at drivers/gpu/drm/i915/intel_uncore.c:795 __unclaimed_reg_debug+0x44/0x50 [i915]
> > [ 4.740155] Unclaimed read from register 0x1e1110
> > [ 4.740168] Modules linked in: i915(+) intel_gtt drm_kms_helper prime_numbers
> > [ 4.740190] CPU: 1 PID: 221 Comm: systemd-udevd Not tainted 4.10.0-rc6+ #384
> > [ 4.740203] Hardware name: / , BIOS PYBSWCEL.86A.0027.2015.0507.1758 05/07/2015
> > [ 4.740220] Call Trace:
> > [ 4.740236] dump_stack+0x4d/0x6f
> > [ 4.740251] __warn+0xc1/0xe0
> > [ 4.740265] warn_slowpath_fmt+0x4a/0x50
> > [ 4.740281] ? insert_work+0x77/0xc0
> > [ 4.740355] ? fwtable_write32+0x90/0x130 [i915]
> > [ 4.740431] __unclaimed_reg_debug+0x44/0x50 [i915]
> > [ 4.740507] fwtable_read32+0xd8/0x130 [i915]
> > [ 4.740575] i915_hpd_irq_setup+0xa5/0x100 [i915]
> > [ 4.740649] intel_hpd_init+0x68/0x80 [i915]
> > [ 4.740716] i915_driver_load+0xe19/0x1380 [i915]
> > [ 4.740784] i915_pci_probe+0x32/0x90 [i915]
> > [ 4.740799] pci_device_probe+0x8b/0xf0
> > [ 4.740815] driver_probe_device+0x2b6/0x450
> > [ 4.740828] __driver_attach+0xda/0xe0
> > [ 4.740841] ? driver_probe_device+0x450/0x450
> > [ 4.740853] bus_for_each_dev+0x5b/0x90
> > [ 4.740865] driver_attach+0x19/0x20
> > [ 4.740878] bus_add_driver+0x166/0x260
> > [ 4.740892] driver_register+0x5b/0xd0
> > [ 4.740906] ? 0xffffffffa0166000
> > [ 4.740920] __pci_register_driver+0x47/0x50
> > [ 4.740985] i915_init+0x5c/0x5e [i915]
> > [ 4.740999] do_one_initcall+0x3e/0x160
> > [ 4.741015] ? __vunmap+0x7c/0xc0
> > [ 4.741029] ? kmem_cache_alloc+0xcf/0x120
> > [ 4.741045] do_init_module+0x55/0x1c4
> > [ 4.741060] load_module+0x1f3f/0x25b0
> > [ 4.741073] ? __symbol_put+0x40/0x40
> > [ 4.741086] ? kernel_read_file+0x100/0x190
> > [ 4.741100] SYSC_finit_module+0xbc/0xf0
> > [ 4.741112] SyS_finit_module+0x9/0x10
> > [ 4.741125] entry_SYSCALL_64_fastpath+0x17/0x98
> > [ 4.741135] RIP: 0033:0x7f8559a140f9
> > [ 4.741145] RSP: 002b:00007fff7509a3e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
> > [ 4.741161] RAX: ffffffffffffffda RBX: 00007f855aba02d1 RCX: 00007f8559a140f9
> > [ 4.741172] RDX: 0000000000000000 RSI: 000055b6db0914f0 RDI: 0000000000000011
> > [ 4.741183] RBP: 0000000000020000 R08: 0000000000000000 R09: 000000000000000e
> > [ 4.741193] R10: 0000000000000011 R11: 0000000000000246 R12: 000055b6db0854d0
> > [ 4.741204] R13: 000055b6db091150 R14: 0000000000000000 R15: 000055b6db035924
> >
> > v2: Set dev_priv->display_irqs_enabled to true for all platforms other
> > than vlv/chv that manually control the display power domain.
> >
> > Fixes: 19625e85c6ec ("drm/i915: Enable polling when we don't have hpd")
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97798
> > Suggested-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> > Cc: Lyude <cpaul@xxxxxxxxxx>
> > Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> > Cc: Hans de Goede <jwrdegoede@xxxxxxxxxxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
>
> lgtm
>
> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Thanks for the idea and fixes,
-Chris
--
Chris Wilson, Intel Open Source Technology Centre