What means 'Attribute is dirty' in the Matter implementation? about arduino

[silabs-bozont]

Hi,

I'm not an expert on all the inner workings of the Matter SDK, so take this with a grain of salt.
The Attribute xxxx is dirty messages are generated by the reporting engine here:

arduino/variants/thingplusmatter_matter/matter_2.1.1/src/app/reporting/Engine.cpp

Line 79 in 956de5d

ChipLogDetail(DataManagement, "<RE:Run> Cluster %" PRIx32 ", Attribute %" PRIx32 " is dirty", aPath.mClusterId,

It means that the attribute (like a certain lightbulb's on/off state) has been marked dirty/changed and a report has to be sent out on the network to notify the other peers that it has changed.

Here you can see when I locally turn the lightbulb off with the button, then the Endpoint 3 - 0x06 (on/off) cluster - 0x00 (on/off) attribute gets marked as dirty - and then the state change is reported on the network:

00> [00:03:23.285][info  ][DL] DeviceLightbulb[Matter bulb]: OFF
00> [00:03:23.285][detail][DMG] Endpoint 3, Cluster 0x0000_0006 update version to 863874bd
00> [00:03:23.285][detail][DMG] Cannot merge the new path into any existing path, create one.
00> [00:03:23.286][detail][DMG] Building Reports for ReadHandler with LastReportGeneration = lu DirtyGeneration = lu
00> [00:03:23.290][detail][DMG] <RE:Run> Cluster 6, Attribute 0 is dirty
00> [00:03:23.290][detail][DMG] Reading attribute: Cluster=0x0000_0006 Endpoint=3 AttributeId=0x0000_0000 (expanded=1)
00> [00:03:23.290][info  ][DL] emberAfExternalAttributeReadCallback
00> [00:03:23.290][info  ][DL] HandleReadLightbulbAttribute: clusterId=6 attrId=0
00> [00:03:23.291][detail][DMG] Fetched 0 events
00> [00:03:23.291][detail][DMG] <RE> Sending report (payload has 39 bytes)...
00> [00:03:23.292][info  ][EM] <<< [E:39967i S:28664 M:8744044] (S) Msg TX to 1:00000000687B3F74 [2EDE] [UDP:[fd30:8724:3fc0:0:1c8f:9090:4848:4940%ot]:57497] --- Type 0001:05 (IM:ReportData)
00> [00:03:23.293][detail][DMG] IM RH moving to [AwaitingReportResponse]
00> [00:03:23.293][detail][DMG] <RE> ReportsInFlight = 1 with readHandler 0, RE has no more messages
00> [00:03:23.293][detail][DMG] All ReadHandler-s are clean, clear GlobalDirtySet
00> [00:03:23.329][detail][IN] UDP Message Received packet nb : 128 SrcAddr : fd30:8724:3fc0:0:1c8f:9090:4848:4940[57497] DestAddr : fd30:8724:3fc0:0:d176:530a:4c4a:999b[5540] Payload Length 42
00> [00:03:23.330][info  ][EM] >>> [E:39967i S:28664 M:2558612 (Ack:8744044)] (S) Msg RX from 1:00000000687B3F74 [2EDE] --- Type 0001:01 (IM:StatusResponse)
00> [00:03:23.331][detail][EM] Found matching exchange: 39967i, Delegate: 0x200088cc
00> [00:03:23.331][detail][EM] Rxd Ack; Removing MessageCounter:8744044 from Retrans Table on exchange 39967i
00> [00:03:23.331][info  ][IM] Received status response, status is 0x00
00> [00:03:23.331][detail][DMG] <RE> OnReportConfirm: NumReports = 0
00> [00:03:23.331][detail][DMG] IM RH moving to [CanStartReporting]
00> [00:03:23.332][info  ][EM] <<< [E:39967i S:28664 M:8744045 (Ack:2558612)] (S) Msg TX to 1:00000000687B3F74 [2EDE] [UDP:[fd30:8724:3fc0:0:1c8f:9090:4848:4940%ot]:57497] --- Type 0000:10 (SecureChannel:StandaloneAck)
00> [00:03:23.333][detail][EM] Flushed pending ack for MessageCounter:2558612

[lboue]

Thanks