# Debug with sysfs or debugfs nodes

To identify the status or update the state, use the <cite>sysfs</cite> and <cite>debugfs</cite> nodes.

Mount <cite>debugfs</cite> to ensure that the <cite>debugfs</cite> file system is accessible for the debug nodes.

> 
> 
> mount -t debugfs none /sys/kernel/debug
>     Copy to clipboard

UFS device state commands

| Required UFS device state information | Command |
| --- | --- |
| Check PA/DL error count | `cat /sys/kernel/debug/ufshcd/1d84000.ufs/stats` |
| Read UFS device gating delay, in ms | `cat /sys/devices/platform/soc@0/1d84000.ufs/clkgate_delay_ms` |
| Read UFS device clocks current frequency at given point | `cat /sys/devices/platform/soc@0/1d84000.ufs/devfreq/1d84000.ufs/cur_freq` |
| Read UFS device I/O scheduler details | `cat /sys/devices/platform/soc@0/1d84000.ufs/devfreq/1d84000.ufs/governor` |
| Read UFS device min frequency during clock scale down | `cat /sys/devices/platform/soc@0/1d84000.ufs/devfreq/1d84000.ufs/min_freq` |
| Read UFS device max frequency during clock scale up | `cat /sys/devices/platform/soc@0/1d84000.ufs/devfreq/1d84000.ufs/max_freq` |
| Read UFS device state active or sleep | `cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/dev_pm` |
| Read UFS device gear information such as HS\_G3, HS\_G4 | `cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/gear` |
| Read UFS device number of lanes | `cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/lane` |
| Read UFS device link state, ACTIVE or HIBERN8 | `cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/link_state` |
| Read UFS device rate information such as Rate A or B | `cat /sys/devices/platform/soc@0/1d84000.ufs/power_info/rate` |
| Read UFS device descriptor information | `ls /sys/devices/platform/soc@0/1d84000.ufs/device_descriptor` |
| Read UFS device health descriptor information | `ls /sys/devices/platform/soc@0/1d84000.ufs/health_descriptor` |
| Read UFS device runtime status information active or suspended | `cat /sys/devices/platform/soc@0/1d84000.ufs/power/runtime_status` |
| Find and/or modify the SPM/RPM level | `cat /sys/devices/platform/soc@0/1d84000.ufs/rpm_lvl`<br><br><br>`cat /sys/devices/platform/soc@0/1d84000.ufs/spm_lvl` |

SD card state commands

| Required SD card state information | Command |
| --- | --- |
| Read SD card error stats information | `cat /sys/kernel/debug/mmc1/err_stats` |
| Read SD card latest error state details | `cat /sys/kernel/debug/mmc1/err_state` |
| Check the current running clock details | `cat /sys/kernel/debug/mmc1/clock` |
| Read the SD card runtime status information (active or suspended) | `cat /sys/devices/platform/soc@0/8804000.mmc/power/runtime_status` |
| Read SD card auto suspend delay time | `cat /sys/devices/platform/soc@0/8804000.mmc/power/autosuspend_delay_ms` |
| Read SD card runtime active time | `cat /sys/devices/platform/soc@0/8804000.mmc/power/runtime_active_time` |
| Read SD card runtime suspend time | `cat /sys/devices/platform/soc@0/8804000.mmc/power/runtime_suspended_time` |
| Read SD card uevent details | `cat /sys/devices/platform/soc@0/8804000.mmc/uevent` |

NVMe state commands

| Required NVMe card state information | Command |
| --- | --- |
| View device model name | `cat /sys/class/nvme/nvme0/model` |
| View device serial number | `cat /sys/class/nvme/nvme0/serial` |
| View current firmware version | `cat /sys/class/nvme/nvme0/firmware_rev` |
| View namespace identifier | `cat /sys/class/nvme/nvme0/nvme0n1/nsid` |
| View namespace size | `cat /sys/class/nvme/nvme0/nvme0n1/size` |
| View the offset in bytes to align the start of the NVMe namespace to the optimal I/O boundary | `cat /sys/class/nvme/nvme0/nvme0n1/alignment_offset` |
| View queue depth | `cat /sys/class/nvme/nvme0/queue_count` |

Last Published: Mar 26, 2025

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