[Intel-gfx] [PATCH] drm/i915: Handle pipe CRC around enabling/disabling pipe.
Maarten Lankhorst
maarten.lankhorst at linux.intel.com
Thu Mar 8 16:38:52 UTC 2018
Op 08-03-18 om 17:21 schreef Ville Syrjälä:
> On Thu, Mar 08, 2018 at 05:02:38PM +0100, Maarten Lankhorst wrote:
>> Op 08-03-18 om 16:22 schreef Ville Syrjälä:
>>> On Thu, Mar 08, 2018 at 01:02:02PM +0100, Maarten Lankhorst wrote:
>>>> This will get rid of the following error:
>>>> [ 74.730271] WARNING: CPU: 4 PID: 0 at drivers/gpu/drm/drm_vblank.c:614 drm_calc_vbltimestamp_from_scanoutpos+0x13e/0x2f0
>>>> [ 74.730311] Modules linked in: vgem snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic i915 x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_intel crct10dif_pclmul snd_hda_codec crc32_pclmul snd_hwdep broadcom ghash_clmulni_intel snd_hda_core bcm_phy_lib snd_pcm tg3 lpc_ich mei_me mei prime_numbers
>>>> [ 74.730353] CPU: 4 PID: 0 Comm: swapper/4 Tainted: G U 4.16.0-rc2-CI-CI_DRM_3822+ #1
>>>> [ 74.730355] Hardware name: Dell Inc. XPS 8300 /0Y2MRG, BIOS A06 10/17/2011
>>>> [ 74.730359] RIP: 0010:drm_calc_vbltimestamp_from_scanoutpos+0x13e/0x2f0
>>>> [ 74.730361] RSP: 0018:ffff88022fb03d10 EFLAGS: 00010086
>>>> [ 74.730365] RAX: ffffffffa0291d20 RBX: ffff88021a180000 RCX: 0000000000000001
>>>> [ 74.730367] RDX: ffffffff820e7db8 RSI: 0000000000000001 RDI: ffffffff82068cea
>>>> [ 74.730369] RBP: ffff88022fb03d70 R08: 0000000000000000 R09: ffffffff815d26d0
>>>> [ 74.730371] R10: 0000000000000000 R11: ffffffffa0161ca0 R12: 0000000000000001
>>>> [ 74.730373] R13: ffff880212448008 R14: ffff880212448330 R15: 0000000000000000
>>>> [ 74.730376] FS: 0000000000000000(0000) GS:ffff88022fb00000(0000) knlGS:0000000000000000
>>>> [ 74.730378] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>>> [ 74.730380] CR2: 000055edcbec9000 CR3: 0000000002210001 CR4: 00000000000606e0
>>>> [ 74.730382] Call Trace:
>>>> [ 74.730385] <IRQ>
>>>> [ 74.730397] drm_get_last_vbltimestamp+0x36/0x50
>>>> [ 74.730401] drm_update_vblank_count+0x64/0x240
>>>> [ 74.730409] drm_crtc_accurate_vblank_count+0x41/0x90
>>>> [ 74.730453] display_pipe_crc_irq_handler+0x176/0x220 [i915]
>>>> [ 74.730497] i9xx_pipe_crc_irq_handler+0xfe/0x150 [i915]
>>>> [ 74.730537] ironlake_irq_handler+0x618/0xa30 [i915]
>>>> [ 74.730548] __handle_irq_event_percpu+0x3c/0x340
>>>> [ 74.730556] handle_irq_event_percpu+0x1b/0x50
>>>> [ 74.730561] handle_irq_event+0x2f/0x50
>>>> [ 74.730566] handle_edge_irq+0xe4/0x1b0
>>>> [ 74.730572] handle_irq+0x11/0x20
>>>> [ 74.730576] do_IRQ+0x5e/0x120
>>>> [ 74.730584] common_interrupt+0x84/0x84
>>>> [ 74.730586] </IRQ>
>>>> [ 74.730591] RIP: 0010:cpuidle_enter_state+0xaa/0x350
>>>> [ 74.730593] RSP: 0018:ffffc9000008beb8 EFLAGS: 00000212 ORIG_RAX: ffffffffffffffde
>>>> [ 74.730597] RAX: ffff880226b80040 RBX: 000000000031fc3e RCX: 0000000000000001
>>>> [ 74.730599] RDX: 0000000000000000 RSI: ffffffff8210fb59 RDI: ffffffff820c02e7
>>>> [ 74.730601] RBP: 0000000000000004 R08: 00000000000040af R09: 0000000000000018
>>>> [ 74.730603] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000004
>>>> [ 74.730606] R13: ffffe8ffffd00430 R14: 0000001166120bf4 R15: ffffffff82294460
>>>> [ 74.730621] ? cpuidle_enter_state+0xa6/0x350
>>>> [ 74.730629] do_idle+0x188/0x1d0
>>>> [ 74.730636] cpu_startup_entry+0x14/0x20
>>>> [ 74.730641] start_secondary+0x129/0x160
>>>> [ 74.730646] secondary_startup_64+0xa5/0xb0
>>>> [ 74.730660] Code: e1 48 c7 c2 b8 7d 0e 82 be 01 00 00 00 48 c7 c7 ea 8c 06 82 e8 64 ec ff ff 48 8b 83 c8 07 00 00 48 83 78 28 00 0f 84 e2 fe ff ff <0f> 0b 45 31 ed e9 db fe ff ff 41 b8 d3 4d 62 10 89 c8 6a 03 41
>>>> [ 74.730754] ---[ end trace 14b1345705b68565 ]---
>>>>
>>>> Changes since v1:
>>>> - Don't try to apply CRC workaround when enabling pipe, it should already be enabled.
>>>> Changes since v2:
>>>> - Make crc functions for !DEBUGFS case inline.
>>>> - Pass intel_crtc to crc functions.
>>>> - Add comments to callsites.
>>>> Changes since v3:
>>>> - Cache selected source to pipe_crc->source.
>>>> - Set pipe_crc->skipped to MIN_INT during disable to close a race condition.
>>>> Changes since v4:
>>>> - Handle fallout from setting pipe_crc->source in irq handler.
>>>>
>>>> Cc: Marta Löfstedt <marta.lofstedt at intel.com>
>>>> Reported-by: Marta Löfstedt <marta.lofstedt at intel.com>
>>>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105185
>>>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
>>>> ---
>>>> drivers/gpu/drm/i915/i915_irq.c | 4 +--
>>>> drivers/gpu/drm/i915/intel_display.c | 10 +++++++
>>>> drivers/gpu/drm/i915/intel_drv.h | 9 ++++++
>>>> drivers/gpu/drm/i915/intel_pipe_crc.c | 53 ++++++++++++++++++++++++++++++-----
>>>> 4 files changed, 67 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
>>>> index ce16003ef048..7807488084fe 100644
>>>> --- a/drivers/gpu/drm/i915/i915_irq.c
>>>> +++ b/drivers/gpu/drm/i915/i915_irq.c
>>>> @@ -1626,7 +1626,7 @@ static void display_pipe_crc_irq_handler(struct drm_i915_private *dev_priv,
>>>> int head, tail;
>>>>
>>>> spin_lock(&pipe_crc->lock);
>>>> - if (pipe_crc->source) {
>>>> + if (pipe_crc->source && !crtc->base.crc.opened) {
>>> Hmm. This is starting to get confusing. Seeing as we now lose the
>>> capability to get all the crcs across the modeset anyway I think I'll
>>> have to revoke my objection to nuking the old interface. Consider
>>> that old nugget acked.
>> Ok thanks. :)
>>>> if (!pipe_crc->entries) {
>>>> spin_unlock(&pipe_crc->lock);
>>>> DRM_DEBUG_KMS("spurious interrupt\n");
>>>> @@ -1666,7 +1666,7 @@ static void display_pipe_crc_irq_handler(struct drm_i915_private *dev_priv,
>>>> * On GEN8+ sometimes the second CRC is bonkers as well, so
>>>> * don't trust that one either.
>>>> */
>>>> - if (pipe_crc->skipped == 0 ||
>>>> + if (pipe_crc->skipped <= 0 ||
>>>> (INTEL_GEN(dev_priv) >= 8 && pipe_crc->skipped == 1)) {
>>>> pipe_crc->skipped++;
>>>> spin_unlock(&pipe_crc->lock);
>>>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>>>> index 331084082545..2933ad38094f 100644
>>>> --- a/drivers/gpu/drm/i915/intel_display.c
>>>> +++ b/drivers/gpu/drm/i915/intel_display.c
>>>> @@ -12147,6 +12147,9 @@ static void intel_update_crtc(struct drm_crtc *crtc,
>>>> if (modeset) {
>>>> update_scanline_offset(intel_crtc);
>>>> dev_priv->display.crtc_enable(pipe_config, state);
>>>> +
>>>> + /* vblanks work again, re-enable pipe CRC. */
>>>> + intel_crtc_enable_pipe_crc(intel_crtc);
>>>> } else {
>>>> intel_pre_plane_update(to_intel_crtc_state(old_crtc_state),
>>>> pipe_config);
>>>> @@ -12327,6 +12330,13 @@ static void intel_atomic_commit_tail(struct drm_atomic_state *state)
>>>>
>>>> if (old_crtc_state->active) {
>>>> intel_crtc_disable_planes(crtc, old_crtc_state->plane_mask);
>>>> +
>>>> + /*
>>>> + * We need to disable pipe CRC before disabling the pipe,
>>>> + * or we race against vblank off.
>>>> + */
>>>> + intel_crtc_disable_pipe_crc(intel_crtc);
>>>> +
>>>> dev_priv->display.crtc_disable(to_intel_crtc_state(old_crtc_state), state);
>>>> intel_crtc->active = false;
>>>> intel_fbc_disable(intel_crtc);
>>>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>>>> index d4368589b355..fce5d3072d97 100644
>>>> --- a/drivers/gpu/drm/i915/intel_drv.h
>>>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>>>> @@ -2138,8 +2138,17 @@ int intel_pipe_crc_create(struct drm_minor *minor);
>>>> #ifdef CONFIG_DEBUG_FS
>>>> int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>>> size_t *values_cnt);
>>>> +void intel_crtc_disable_pipe_crc(struct intel_crtc *crtc);
>>>> +void intel_crtc_enable_pipe_crc(struct intel_crtc *crtc);
>>>> #else
>>>> #define intel_crtc_set_crc_source NULL
>>>> +static inline void intel_crtc_disable_pipe_crc(struct intel_crtc *crtc)
>>>> +{
>>>> +}
>>>> +
>>>> +static inline void intel_crtc_enable_pipe_crc(struct intel_crtc *crtc)
>>>> +{
>>>> +}
>>>> #endif
>>>> extern const struct file_operations i915_display_crc_ctl_fops;
>>>> #endif /* __INTEL_DRV_H__ */
>>>> diff --git a/drivers/gpu/drm/i915/intel_pipe_crc.c b/drivers/gpu/drm/i915/intel_pipe_crc.c
>>>> index 1f5cd572a7ff..4f367c16e9e5 100644
>>>> --- a/drivers/gpu/drm/i915/intel_pipe_crc.c
>>>> +++ b/drivers/gpu/drm/i915/intel_pipe_crc.c
>>>> @@ -569,7 +569,8 @@ static void hsw_pipe_A_crc_wa(struct drm_i915_private *dev_priv,
>>>> static int ivb_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
>>>> enum pipe pipe,
>>>> enum intel_pipe_crc_source *source,
>>>> - uint32_t *val)
>>>> + uint32_t *val,
>>>> + bool set_wa)
>>>> {
>>>> if (*source == INTEL_PIPE_CRC_SOURCE_AUTO)
>>>> *source = INTEL_PIPE_CRC_SOURCE_PF;
>>>> @@ -582,7 +583,7 @@ static int ivb_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
>>>> *val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_SPRITE_IVB;
>>>> break;
>>>> case INTEL_PIPE_CRC_SOURCE_PF:
>>>> - if ((IS_HASWELL(dev_priv) ||
>>>> + if (set_wa && (IS_HASWELL(dev_priv) ||
>>>> IS_BROADWELL(dev_priv)) && pipe == PIPE_A)
>>>> hsw_pipe_A_crc_wa(dev_priv, true);
>>>>
>>>> @@ -600,7 +601,8 @@ static int ivb_pipe_crc_ctl_reg(struct drm_i915_private *dev_priv,
>>>>
>>>> static int get_new_crc_ctl_reg(struct drm_i915_private *dev_priv,
>>>> enum pipe pipe,
>>>> - enum intel_pipe_crc_source *source, u32 *val)
>>>> + enum intel_pipe_crc_source *source, u32 *val,
>>>> + bool set_wa)
>>>> {
>>>> if (IS_GEN2(dev_priv))
>>>> return i8xx_pipe_crc_ctl_reg(source, val);
>>>> @@ -611,7 +613,7 @@ static int get_new_crc_ctl_reg(struct drm_i915_private *dev_priv,
>>>> else if (IS_GEN5(dev_priv) || IS_GEN6(dev_priv))
>>>> return ilk_pipe_crc_ctl_reg(source, val);
>>>> else
>>>> - return ivb_pipe_crc_ctl_reg(dev_priv, pipe, source, val);
>>>> + return ivb_pipe_crc_ctl_reg(dev_priv, pipe, source, val, set_wa);
>>>> }
>>>>
>>>> static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
>>>> @@ -636,7 +638,7 @@ static int pipe_crc_set_source(struct drm_i915_private *dev_priv,
>>>> return -EIO;
>>>> }
>>>>
>>>> - ret = get_new_crc_ctl_reg(dev_priv, pipe, &source, &val);
>>>> + ret = get_new_crc_ctl_reg(dev_priv, pipe, &source, &val, true);
>>>> if (ret != 0)
>>>> goto out;
>>>>
>>>> @@ -916,7 +918,7 @@ int intel_pipe_crc_create(struct drm_minor *minor)
>>>> int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>>> size_t *values_cnt)
>>>> {
>>>> - struct drm_i915_private *dev_priv = crtc->dev->dev_private;
>>>> + struct drm_i915_private *dev_priv = to_i915(crtc->dev);
>>>> struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[crtc->index];
>>>> enum intel_display_power_domain power_domain;
>>>> enum intel_pipe_crc_source source;
>>>> @@ -934,10 +936,11 @@ int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>>> return -EIO;
>>>> }
>>>>
>>>> - ret = get_new_crc_ctl_reg(dev_priv, crtc->index, &source, &val);
>>>> + ret = get_new_crc_ctl_reg(dev_priv, crtc->index, &source, &val, true);
>>>> if (ret != 0)
>>>> goto out;
>>>>
>>>> + pipe_crc->source = source;
>>>> I915_WRITE(PIPE_CRC_CTL(crtc->index), val);
>>>> POSTING_READ(PIPE_CRC_CTL(crtc->index));
>>>>
>>>> @@ -959,3 +962,39 @@ int intel_crtc_set_crc_source(struct drm_crtc *crtc, const char *source_name,
>>>>
>>>> return ret;
>>>> }
>>>> +
>>>> +void intel_crtc_enable_pipe_crc(struct intel_crtc *intel_crtc)
>>>> +{
>>>> + struct drm_crtc *crtc = &intel_crtc->base;
>>>> + struct drm_i915_private *dev_priv = to_i915(crtc->dev);
>>>> + struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[crtc->index];
>>>> + u32 val = 0;
>>>> +
>>>> + if (!crtc->crc.opened)
>>>> + return;
>>>> +
>>>> + if (get_new_crc_ctl_reg(dev_priv, crtc->index, &pipe_crc->source, &val, false) < 0)
>>>> + return;
>>>> +
>>>> + /* Don't need pipe_crc->lock here, IRQs are not generated. */
>>>> + pipe_crc->skipped = 0;
>>>> +
>>>> + I915_WRITE(PIPE_CRC_CTL(crtc->index), val);
>>>> + POSTING_READ(PIPE_CRC_CTL(crtc->index));
>>>> +}
>>>> +
>>>> +void intel_crtc_disable_pipe_crc(struct intel_crtc *intel_crtc)
>>>> +{
>>>> + struct drm_crtc *crtc = &intel_crtc->base;
>>>> + struct drm_i915_private *dev_priv = to_i915(crtc->dev);
>>>> + struct intel_pipe_crc *pipe_crc = &dev_priv->pipe_crc[crtc->index];
>>>> +
>>>> + /* Swallow crc's until we stop generating them. */
>>>> + spin_lock_irq(&pipe_crc->lock);
>>>> + pipe_crc->skipped = INT_MIN;
>>>> + spin_unlock_irq(&pipe_crc->lock);
>>> Does this mean the hw can still generate a crc interrupt after the
>>> PIPE_CRC_CTL has been cleared?
>> I think at most just 1, but if modeset disable is fast enough we could theoretically hit it after vblank off probably.
>> Hence the extra paranoia of setting skipped before synchronize_irq, at that point we know for sure that any
>> CRC will be swallowed after disable_pipe_crc returns, even on a crazy -rt kernel.
> OK. So I guess we're not entirely sure then. I guess being paranoid
> doesn't hurt though
>
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> still holds. Not that it did much good on the previous iteration :/
>
Yeah on second inspection it looks like revision 2 was working correctly and it fixed 105185, but I think the extra paranoia is good regardless.
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