[Intel-gfx] [PATCH v2] drm/i915: Only enable hotplug interrupts if the display interrupts are enabled

[Chris Wilson]

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 at linux.intel.com>
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Lyude <cpaul at redhat.com>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Hans de Goede <jwrdegoede at fedoraproject.org>
> > Cc: stable at vger.kernel.org
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> 
> lgtm
> 
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Thanks for the idea and fixes,
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre