This must be some LWLA16 regression (not the same as the one fixed in 42d14d9108de61ead41aebe74d668239ee7d5089 though), since it used to work in the past. LWLA1034 is not affected and works fine.

No matter which settings are used, the driver/hardware will always only grab 2 samples.

This is with a firmware extracted from vendor software:

9ea144768afdd3092712075c23eadca4  sysclk-lwla1016-100.rbf
339d71ee799d3d3dbdcbcf1a00aa9f33  sysclk-lwla1016-100-ts.rbf
77fe7158ee53dcbed3bf390ee753594f  sysclk-lwla1016-200.rbf
e5246f3c1b9e3a34b570af9d50e02cbf  sysclk-lwla1016-200-ts.rbf
d9f587c9f53d0706f25658bc5580e4f7  sysclk-lwla1016-250.rbf
9d8c284bdbcfbad88aab9c2a79eb783d  sysclk-lwla1016-250-ts.rbf

Error:

$ LD_LIBRARY_PATH=$HOME/sr/lib ~/sr/bin/sigrok-cli -d sysclk-lwla --samples 50 -l 5
sr: [00:00.000002] log: libsigrok loglevel set to 5.
sr: [00:00.000053] backend: libsigrok 0.6.0-git-42d14d91/4:0:0 (rt: 0.6.0-git-42d14d91/4:0:0).
sr: [00:00.000116] backend: Libs: glib 2.54.1 (rt: 2.54.1/5401:1), libzip 1.1.2, libserialport 0.1.1/1:0:1 (rt: 0.1.1/1:0:1), libusb-1.0 1.0.21.11156, libftdi 1.3.
sr: [00:00.000126] backend: Host: x86_64-pc-linux-gnu, little-endian.
sr: [00:00.000135] backend: SCPI backends: TCP, RPC, serial, USBTMC.
sr: [00:00.000172] backend: Sanity-checking all drivers.
sr: [00:00.000184] backend: Sanity-checking all input modules.
sr: [00:00.000191] backend: Sanity-checking all output modules.
sr: [00:00.000197] backend: Sanity-checking all transform modules.
srd: libsigrokdecode loglevel set to 5.
sr: [00:00.003773] hwdriver: Scan found 1 devices (sysclk-lwla).
sr: [00:00.003827] device: sysclk-lwla: Opening device instance.
sr: [00:00.003834] usb: Trying to open USB device 2.81.
sr: [00:00.003881] usb: Opened USB device (VID:PID = 2961:6688, bus.address = 2.81).
sr: [00:00.045095] resource: SIGROK_FIRMWARE_DIR environment variable not set, ignoring.
sr: [00:00.045318] resource: Attempt to open '/home/uwe/.local/share/sigrok-firmware/sysclk-lwla1016-100-ts.rbf' failed: No such file or directory
sr: [00:00.045363] resource: Opened '/home/uwe/sr/share/sigrok-firmware/sysclk-lwla1016-100-ts.rbf'.
sr: [00:00.045581] sysclk-lwla: Downloading FPGA bitstream 'sysclk-lwla1016-100-ts.rbf'.
sr: [00:00.857458] sysclk-lwla: FPGA bitstream download of 70592 bytes done.
sr: [00:00.888258] hwdriver: sr_config_set(): key 50001 (limit_samples) sdi 0x562debb6dd90 cg NULL -> uint64 50
sr: [00:00.888383] session: Using thread-default main context.
sr: [00:00.888392] session: Starting.
sr: [00:00.888398] hwdriver: sysclk-lwla: Starting acquisition.
sr: [00:00.888489] sysclk-lwla: Acquisition sample count limit 50.
sr: [00:00.888498] sysclk-lwla: Internal clock, samplerate 100000000.
sr: [00:00.889337] std: sysclk-lwla: Sending SR_DF_HEADER packet.
sr: [00:00.889367] session: Running transform module 'nop'.
sr: [00:00.889374] transform/nop: Received packet of type 10000, passing on unmodified.
sr: [00:00.889383] session: bus: Received SR_DF_HEADER packet.
cli: Received SR_DF_HEADER.
sr: [00:00.889634] hwdriver: sr_config_get(): key 30000 (samplerate) sdi 0x562debb6dd90 cg NULL -> uint64 100000000
sr: [00:00.889702] sysclk-lwla: Acquisition started.
sr: [00:00.990393] sysclk-lwla: Captured 2 words, 100 ms, status 0x74.
sr: [00:00.990457] sysclk-lwla: Capture triggered.
sr: [00:00.990464] sysclk-lwla: Time limit reached, stopping capture.
sr: [00:00.990676] sysclk-lwla: 2 words in capture buffer.
sr: [00:00.990835] session: Running transform module 'nop'.
sr: [00:00.990852] transform/nop: Received packet of type 10004, passing on unmodified.
sr: [00:00.990861] session: bus: Received SR_DF_LOGIC packet (4 bytes, unitsize = 2).
cli: Received SR_DF_LOGIC (4 bytes, unitsize = 2).
sr: [00:00.990930] hwdriver: sr_config_get(): key 30000 (samplerate) sdi 0x562debb6dd90 cg NULL -> uint64 100000000
libsigrok 0.6.0-git-42d14d91
Acquisition with 16/16 channels at 100 MHz
sr: [00:00.991154] sysclk-lwla: Acquisition stopped.
sr: [00:00.991366] std: sysclk-lwla: Sending SR_DF_END packet.
sr: [00:00.991377] session: Running transform module 'nop'.
sr: [00:00.991385] transform/nop: Received packet of type 10001, passing on unmodified.
sr: [00:00.991392] session: bus: Received SR_DF_END packet.
CH1:00
CH2:00
CH3:11
CH4:00
CH5:11
CH6:11
CH7:00
CH8:00
CH9:11
CH10:00
CH11:00
CH12:00
CH13:00
CH14:00
CH15:00
CH16:00
cli: Received SR_DF_END.
Device only sent 2 samples.
sr: [00:00.991442] usb: usb_source_finalize
sr: [00:00.991479] session: Stopped.
sr: [00:00.991535] hwdriver: Cleaning up all drivers.
sr: [00:00.991627] usb: Closed USB device 2.81.