From b15b9c6cd0e8d83ec12a868c10cf184217f51309 Mon Sep 17 00:00:00 2001 From: Christof Arnosti Date: Sun, 8 Mar 2020 15:25:55 +0100 Subject: usb-serial-for-android: Implement timeout-handling Since the Android USB stack and subsequently the usb-serial-for-android driver have problems with read-timeouts, the read-timeout is now implemented in AndroidSerial.java. Also, DC_STATUS_TIMEOUT is returned if there are less bytes returned than expected. Different chipsets seem to behave differently with usb-serial-for-android. On CP210x the read blocks until there is some data here, but on FTDI the chip seems to return whatever is currently in the buffer (so 0 bytes if the buffer is empty). This different behaviour should be mitigated by the changes by this commit. Signed-off-by: Christof Arnosti --- .../src/org/subsurfacedivelog/mobile/AndroidSerial.java | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'android-mobile/src/org/subsurfacedivelog/mobile') diff --git a/android-mobile/src/org/subsurfacedivelog/mobile/AndroidSerial.java b/android-mobile/src/org/subsurfacedivelog/mobile/AndroidSerial.java index 59b8dc9e9..1193b0ceb 100644 --- a/android-mobile/src/org/subsurfacedivelog/mobile/AndroidSerial.java +++ b/android-mobile/src/org/subsurfacedivelog/mobile/AndroidSerial.java @@ -19,6 +19,7 @@ import java.util.Queue; import java.util.List; import java.util.LinkedList; import java.lang.Math; +import java.util.Date; public class AndroidSerial { @@ -221,17 +222,20 @@ public class AndroidSerial { Log.d(TAG, "read length: " + data.length); int toReadFromHwLength = data.length - readBuffer.size(); - int arraylength = (toReadFromHwLength % 64) != 0 ? toReadFromHwLength + (64 - (toReadFromHwLength % 64)): toReadFromHwLength; // use blocks of 64 for reading - // When we don't have enough in the buffer, try to read from HW - if (toReadFromHwLength > 0) { + long startTime = (new Date()).getTime(); + + // while we don't have enough in the buffer, try to read from HW until there is enough or timeout is reached. + while (toReadFromHwLength > 0 && (startTime + timeout > (new Date()).getTime() || timeout == 0)) { // Read and append to buffer byte[] readFromHwData = new byte[arraylength]; - int actuallyReadFromHwLength = usbSerialPort.read(readFromHwData, 0); // With this it works... But the timeout is ignored! Fix this! + int actuallyReadFromHwLength = usbSerialPort.read(readFromHwData, 0); // This behaves differently on different chipsets. CP210x blocks, FTDI seems to return instantly. for (int i = 0; i < actuallyReadFromHwLength; i++ ) { readBuffer.add(readFromHwData[i]); } + toReadFromHwLength = data.length - readBuffer.size(); + arraylength = (toReadFromHwLength % 64) != 0 ? toReadFromHwLength + (64 - (toReadFromHwLength % 64)): toReadFromHwLength; // use blocks of 64 for reading } //Log.d(TAG, "read buffer: " + printQueue(readBuffer)); -- cgit v1.2.3-70-g09d2