This is a patch to fix a problem that occurs at high baud rates in the cpm uart interrupt handling.
In cpm_uart_int(), the existing code reads the event register, processes the events, and then clears bits in the event register before returning. The problem here is that sometimes event processing generates new events quite quickly (i.e. at higher baud rates, the transmit interrupt handler puts another character into an SCC's transmit buffer and the SCC clears the READY bit almost immediately). In this case, the second interrupt can be missed because the scc_scce event register gets cleared after processing the first. The port can get hung. The fix adds a while loop. It reads the event register saving its value in the local variable 'events' (as before) then clears the event register in the device immediately. It processes the events and tests the event register again handling new events that might get generated during handling. Any comment ? Guillaume. -- ======================================= Guillaume Autran Senior Software Engineer MRV Communications, Inc. Tel: (978) 952-4932 office E-mail: gautran at mrv.com ======================================= -------------- next part -------------- An HTML attachment was scrubbed... URL: http://ozlabs.org/pipermail/linuxppc-embedded/attachments/20050519/76f1107a/attachment.htm -------------- next part -------------- An embedded and charset-unspecified text was scrubbed... Name: cpm_uart_core.patch Url: http://ozlabs.org/pipermail/linuxppc-embedded/attachments/20050519/76f1107a/attachment.txt
