Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
> i915_drpc_info missed covering a few register read with the runtime pm
> wakelock. Be simple and cover the entire function with a single wakelock
> so that new additions are not similarly missed in future.
>
> WARNING: CPU: 2 PID: 1334 at drivers/gpu/drm/i915/intel_drv.h:1743 gen6_read32+0x192/0x1e0 [i915]
> RPM wakelock ref not held during HW access
> Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver netconsole nfsd auth_rpcgss ipmi_watchdog ipmi_poweroff ipmi_devintf ipmi_msghandler overlay btrfs xor raid6_pq dm_mod sg sd_mod snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic ata_generic pata_acpi intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_intel kvm_intel snd_hda_codec kvm eeepc_wmi irqbypass snd_hda_core crct10dif_pclmul crc32_pclmul crc32c_intel asus_wmi sparse_keymap ghash_clmulni_intel snd_hwdep i915 rfkill ppdev pcbc aesni_intel ata_piix crypto_simd glue_helper snd_pcm pata_via cryptd pcspkr snd_timer drm_kms_helper syscopyarea snd sysfillrect libata sysimgblt fb_sys_fops soundcore shpchp drm wmi parport_pc parport tpm_infineon video
> CPU: 2 PID: 1334 Comm: php5 Not tainted 4.10.0-rc8-01615-g1f58c8e #1
> Hardware name: System manufacturer System Product Name/P8H67-M PRO, BIOS 1002 04/01/2011
> Call Trace:
> dump_stack+0x63/0x8a
> __warn+0xcb/0xf0
> warn_slowpath_fmt+0x4f/0x60
> ? seq_vprintf+0x35/0x50
> gen6_read32+0x192/0x1e0 [i915]
> i915_drpc_info+0x55d/0x990 [i915]
> seq_read+0xf2/0x3b0
> full_proxy_read+0x51/0x80
> __vfs_read+0x28/0x130
> ? security_file_permission+0x9b/0xc0
> ? rw_verify_area+0x4e/0xb0
> vfs_read+0xa8/0x170
> SyS_read+0x46/0xa0
> entry_SYSCALL_64_fastpath+0x1a/0xa9
> RIP: 0033:0x7fd97bf175a0
> RSP: 002b:00007ffdf730db68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
> RAX: ffffffffffffffda RBX: 00007fd978028738 RCX: 00007fd97bf175a0
> RDX: 0000000000002000 RSI: 00007fd97740e0d8 RDI: 0000000000000005
> RBP: 0000000000000001 R08: 0000000000e97840 R09: 00007fd977ef8d58
> R10: 0000000000000027 R11: 0000000000000246 R12: 00007fd977ef8d58
> R13: 0000000000000000 R14: 0000000000eb4640 R15: 0000000000000000
>
> Reported-by: kernel test robot <xiaolong.ye@xxxxxxxxx>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
While reading this I pondered if mutexing the whole read sequence
would add value. To give 'atomic' snapshot of state.
But that is a separate issue.
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_debugfs.c | 38 +++++++++++++------------------------
> 1 file changed, 13 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index 3e36599c0b58..44c7db48d349 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -1400,14 +1400,10 @@ static int ironlake_drpc_info(struct seq_file *m)
> u32 rgvmodectl, rstdbyctl;
> u16 crstandvid;
>
> - intel_runtime_pm_get(dev_priv);
> -
> rgvmodectl = I915_READ(MEMMODECTL);
> rstdbyctl = I915_READ(RSTDBYCTL);
> crstandvid = I915_READ16(CRSTANDVID);
>
> - intel_runtime_pm_put(dev_priv);
> -
> seq_printf(m, "HD boost: %s\n", yesno(rgvmodectl & MEMMODE_BOOST_EN));
> seq_printf(m, "Boost freq: %d\n",
> (rgvmodectl & MEMMODE_BOOST_FREQ_MASK) >>
> @@ -1476,14 +1472,10 @@ static int vlv_drpc_info(struct seq_file *m)
> struct drm_i915_private *dev_priv = node_to_i915(m->private);
> u32 rpmodectl1, rcctl1, pw_status;
>
> - intel_runtime_pm_get(dev_priv);
> -
> pw_status = I915_READ(VLV_GTLC_PW_STATUS);
> rpmodectl1 = I915_READ(GEN6_RP_CONTROL);
> rcctl1 = I915_READ(GEN6_RC_CONTROL);
>
> - intel_runtime_pm_put(dev_priv);
> -
> seq_printf(m, "Video Turbo Mode: %s\n",
> yesno(rpmodectl1 & GEN6_RP_MEDIA_TURBO));
> seq_printf(m, "Turbo enabled: %s\n",
> @@ -1512,21 +1504,12 @@ static int vlv_drpc_info(struct seq_file *m)
> static int gen6_drpc_info(struct seq_file *m)
> {
> struct drm_i915_private *dev_priv = node_to_i915(m->private);
> - struct drm_device *dev = &dev_priv->drm;
> u32 rpmodectl1, gt_core_status, rcctl1, rc6vids = 0;
> u32 gen9_powergate_enable = 0, gen9_powergate_status = 0;
> unsigned forcewake_count;
> - int count = 0, ret;
> -
> - ret = mutex_lock_interruptible(&dev->struct_mutex);
> - if (ret)
> - return ret;
> - intel_runtime_pm_get(dev_priv);
> -
> - spin_lock_irq(&dev_priv->uncore.lock);
> - forcewake_count = dev_priv->uncore.fw_domain[FW_DOMAIN_ID_RENDER].wake_count;
> - spin_unlock_irq(&dev_priv->uncore.lock);
> + int count = 0;
>
> + forcewake_count = READ_ONCE(dev_priv->uncore.fw_domain[FW_DOMAIN_ID_RENDER].wake_count);
> if (forcewake_count) {
> seq_puts(m, "RC information inaccurate because somebody "
> "holds a forcewake reference \n");
> @@ -1546,13 +1529,11 @@ static int gen6_drpc_info(struct seq_file *m)
> gen9_powergate_enable = I915_READ(GEN9_PG_ENABLE);
> gen9_powergate_status = I915_READ(GEN9_PWRGT_DOMAIN_STATUS);
> }
> - mutex_unlock(&dev->struct_mutex);
> +
> mutex_lock(&dev_priv->rps.hw_lock);
> sandybridge_pcode_read(dev_priv, GEN6_PCODE_READ_RC6VIDS, &rc6vids);
> mutex_unlock(&dev_priv->rps.hw_lock);
>
> - intel_runtime_pm_put(dev_priv);
> -
> seq_printf(m, "Video Turbo Mode: %s\n",
> yesno(rpmodectl1 & GEN6_RP_MEDIA_TURBO));
> seq_printf(m, "HW control enabled: %s\n",
> @@ -1629,13 +1610,20 @@ static int gen6_drpc_info(struct seq_file *m)
> static int i915_drpc_info(struct seq_file *m, void *unused)
> {
> struct drm_i915_private *dev_priv = node_to_i915(m->private);
> + int err;
> +
> + intel_runtime_pm_get(dev_priv);
>
> if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
> - return vlv_drpc_info(m);
> + err = vlv_drpc_info(m);
> else if (INTEL_GEN(dev_priv) >= 6)
> - return gen6_drpc_info(m);
> + err = gen6_drpc_info(m);
> else
> - return ironlake_drpc_info(m);
> + err = ironlake_drpc_info(m);
> +
> + intel_runtime_pm_put(dev_priv);
> +
> + return err;
> }
>
> static int i915_frontbuffer_tracking(struct seq_file *m, void *unused)
> --
> 2.11.0
>
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