Sensor Debug SOP¶

REVISION HISTORY¶

Revision No.	Description	Date
1.0	Initial release	06/19/2024
1.1	Added ISP FIFO FULL case	07/05/2024
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Introduction¶

This document is written for FAE and software development personnel, aiming to introduce how to perform preliminary investigation when customers encounter Sensor-related issues during development, and what information needs to be provided to RD for analysis after determining it is a Sigmastar SDK issue.

1. Common Basic Operations and Commands for Sensor Debugging¶

1.1 Sensor Setting Information¶

Debug information

#cat /proc/mi_modules/mi_sensor/debug_hal/sensor_info

Debug information analysis

Records sensor pad related information.

Parameter description

Parameter		Description
EarlyInit	Enable	EarlyInit enable or not
Fps x1000		Frame rate (fps)
Plane	Name	Sensor name
	Sensor output	Output width and height
	Shutter	Sensor shutter
	Gain	Sensor gain
	Vc num	HDR channel number
	BayerId	Bayer id
	PixPrecision	Bayer id
	Pixel	Pixel format

Debug description

1.2 Confirm MIPI CSI Receive Information¶

Debug information

#cat /proc/mi_modules/mi_sensor/debug_hal/csi_info

Debug information analysis

Check MIPI related information.

Parameter description

Parameter	Description
IDEAL_RECV_SIZE	Ideally received (width, height)
CUR_RECV_SIZE	Currently received (width, height)
LAST_ERR_SIZE	When Mac layer has line end interrupt and currently received width and height do not match ideally received width and height, records the current (width, height).

1.3 Confirm MIPI CSI Error Interrupt Status¶

Debug information

#echo <Sensor Pad> <csi_err_mask> > cat /proc/mi_modules/mi_sensor/debug_hal/csi_dbg_mask
#echo <Sensor Pad> <csi_rpt_mask> > cat /proc/mi_modules/mi_sensor/debug_hal/csi_rpt_mask
#cat cat /proc/mi_modules/mi_sensor/debug_hal/csi_ints

<csi_err_mask>: Mask bit description as follows
[14]: overrun_err
[13]: ls_err
[12]: le_err
[11]: con_fs_err (consecutive fs)
[10]: con_fe_err (consecutive fe)
[9]: raw10_lens_err (not 5n alignment)
[8]: pa_wc_eq0 (payload word count equal to 0)
[7]: crc error
[6]: ecc 2bit error
[5]: frame end error
[4]: frame start error (hardware auto-ignore)
[3]: ecc 1bit error (hardware auto-correct)
[2]: ph_lens_err (packet header lengths error)
[1]: pa_lens_err (payload lengths error shorter than wc)
[0]: dt_err (reserved and not supported data type)

<csi_rpt_mask>: Mask bit description as follows
[6]: report vc0 frame done
[5]: report vc1 frame done
[4]: report vc2 frame done
[3]: report vc3 frame done
[2]: report generic 8 bit short packet data
[1]: report frame number
[0]: report line number

Debug information analysis

Check the occurrence count of csi_err and csi_rpt related interrupts. Typically when MIPI sensor VIF receives data abnormally, this command can be used to analyze the issue.
Parameter description

Parameter		Description
CSI_ERR	DT	Unsupported data type
	PA_LENS	Packet payload length abnormal, shorter than WC
	PH_LENS	Packet header length abnormal, normally 32 bits
	ECC_ONEBIT	ECC 1 bit abnormal, hardware auto-correct
	FRAME_START	Frame start abnormal
	FRAME_END	Frame end abnormal
	ECC_TWOBIT	ECC two bit abnormal
	CRC	CRC check abnormal
	PA_WC_EQ0	Packet payload word count equal to 0
	RAW10_LENS	Not used
	CON_FE	Consecutive frame end abnormal
	CON_FS	Consecutive frame start abnormal
	LE	Line end abnormal
	LE	Line start abnormal
	OVERRUN	TX faster than RX
CSI_RPT	LINE_NUM	Report line number
	FRAME_NUM	Report frame number
	SHORT_PKT	Report generic 8 bit short packet data
	VC3_DONE	Report VC3 frame done
	VC2_DONE	Report VC2 frame done
	VC1_DONE	Report VC1 frame done
	VC0_DONE	Report VC0 frame done

2. Basic Analysis of Common Issues¶

2.1 ISP FIFO FULL¶

Case A. When ISP reports ISP FIFO FULL is because previous stage VIF has insufficient data, can first investigate Sensor output signals¶

    a. Confirm not executing app, only execute cmd: echo enable "snrpad" > /dev/sensorif
       Example:
       snrpad 0

       echo enable 0 > /dev/sensorif

    b. Then through the MIPI CSI debug interface described above, confirm if corresponding MIPI CSI information is correct
    c. If incorrect, can first investigate if MIPI CSI signal timing meets our specifications, and provide MIPI CSI info and MIPI error interrupt status information to SW RD for confirmation

Case B. When linear frame mode outputs normally, but realtime mode encounters ISP FIFO FULL, can first investigate Sensor output signals¶

       Example:
       Frame rate 30fps, represents frame interval of 33.3ms, measure MIPI CSI signal data pins,
       confirm the ratio of valid data and blanking, hope to set blanking to about 1ms for best results

Case C. When hdr frame mode outputs normally, but realtime mode encounters ISP FIFO FULL¶

    a. Confirm ISP ring mode setting size
    b. Read sensor short exposure information, check if it's greater than ISP ring mode setting size
       Example:
       ISP ring size set to 1/8:
       Image height is 1080, so 1080 x (1/8) = 135

       Represents that short exposure cannot exceed the time of 135 lines, otherwise there will be ISP P1 FIFO FULL error

       Additional note:
       HDR long exposure data is output first, followed by short exposure data. The time from the start of long exposure to the start of short exposure is the adjustable exposure time for short exposure.
       In HDR realtime mode, long exposure data coming in is first written to wdma. This wdma is ring buf mechanism, while short exposure is directly output to ISP.
       Using the above example, when incoming long exposure lines count writes from 0 to 134 lines, the 135th line will return to the source and overwrite.
       If short exposure comes later, ISP will encounter situation where data from long exposure and short exposure cannot match, causing ISP P1 FIFO FULL error.

Case D. When HDR Frame mode outputs normally, but Realtime mode encounters ISP FIFO FULL, accompanied by purple blocks on the left¶

    a. Issue of long and short exposure not synchronized, recommend feedback to SW RD