Avoid obsolete samples in the RX Stream #255
Comments
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It appears that the stale samples in the stream can be discarded by opening the device and closing it again. This should give a clue as to where the samples are still being buffered - in the FX3 or in the FPGA. My inkling is that it is in the FX3 somewhere, but further analysis is required to squash this bug. Thanks for being persistent on this issue, @kartarr! |
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The DMA channel is cleared on set/clear_feature(ep_halt). Need to make sure that both the EP and GPIF DMA buffers are cleared since this isn't done automatically with the FX3. Assigning to @jynik since he is most familiar with this functionality. |
jynik
changed the title
Stale RX and TX samples have been reported (issue #255). This occurs because the CyU3PResetEp() call does not reset DMA channels and their underlying DMA buffers, nor does it clear the DMA buffers associated with an endpoint. Use of the existing ClearDMAChannel() as is would have required some ridiculous shoehorning, so some cleanup was done: - Endpoint halt & ACK operations have been removed from ClearDMAChannel(). These operations are outside of the scope of clearing DMA buffers, and have been moved to their respective locations in handling set/clear halt endpoint requests. - reset_endpoint() has been added to the NuandApplication function table. Internally, this operation is now used in performing the halt_endpoint() operation. - Misc return value checks added. Granted, these don't help much as there's no accessible debug log.
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I've pushed a pending fix to dev-issue_255. @robertghilduta, @bpadalino, and @kartarr -- Could I trouble you guys to take a look and test drive this as well? For your convenience, a pre-built image is up here (The above file will be removed after this issue is resolved.) |
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Confirmed that it appears fixed to me, but input fro @kartarr is still recommended. |
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Hi guys... However I can still notice the phase jump between samples 9727-9728. It seems like a variable number of samples is missing. I am using sync interface. The occurrence is rare, irregular and impossible to detect (no gap between the timestamps if meta enabled). I am trying to find how to reproduce or detect it, but in the moment, I can't find any hints. Opening the device and closing it again doesn't have impact on it. One observation: If I reopen device between measurements, in some cases there is a gap in the timestamps between packets 22 and 23 (i.e. 24272 followed by 40904). I think, this could have a connection to the phase jumps. Without reopen, the timestamps are always consistent. |
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I'll plan to merge fix for the stale samples in to master, tag and post a new firmware, and mark this issue closed. Let's plan to open a separate issue tracker item for the phase jump. @robertghilduta, @bpadalino and I are actively working on getting timestamp support into libbladeRF, we will likely run into this while running some tests. @kartarr, your above observations pertain to issue #265, correct? If so, let's copy your observations into that issue, to keep the thread self-contained. |
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Sure, you made a good job... I am not sure if my observations is the same as in #265 or new issue. It seems to be more general problem. I will make a couple more tests to make the decision... |
Stale RX and TX samples have been reported (issue #255). This occurs because the CyU3PResetEp() call does not reset DMA channels and their underlying DMA buffers, nor does it clear the DMA buffers associated with an endpoint. Use of the existing ClearDMAChannel() as is would have required some ridiculous shoehorning, so some cleanup was done: - Endpoint halt & ACK operations have been removed from ClearDMAChannel(). These operations are outside of the scope of clearing DMA buffers, and have been moved to their respective locations in handling set/clear halt endpoint requests. - reset_endpoint() has been added to the NuandApplication function table. Internally, this operation is now used in performing the halt_endpoint() operation. - Misc return value checks added. Granted, these don't help much as there's no accessible debug log.
Stale RX and TX samples have been reported (issue #255). This occurs because the CyU3PResetEp() call does not reset DMA channels and their underlying DMA buffers, nor does it clear the DMA buffers associated with an endpoint. Use of the existing ClearDMAChannel() as is would have required some ridiculous shoehorning, so some cleanup was done: - Endpoint halt & ACK operations have been removed from ClearDMAChannel(). These operations are outside of the scope of clearing DMA buffers, and have been moved to their respective locations in handling set/clear halt endpoint requests. - reset_endpoint() has been added to the NuandApplication function table. Internally, this operation is now used in performing the halt_endpoint() operation. - Misc return value checks added. Granted, these don't help much as there's no accessible debug log.
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Fix introduced in 55713e8, which is included in FW v1.7.1. |
There is a phase jump after the first 9728 (19x512) samples in the RX signal. In the following measurements without re-opening the device, this samples are filled with old data.
The quick fix is to draft first 9728 samples from the RX signal.
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