Friday 04 September 2009 07:39:36 Eero Nurkkala wrote:
Register values should not get corrupted. Could you please point out the registers that may get corrupted? Do they get corrupted during audio play? I haven't seen corrupted register values.
Hi Eero,
Please have a look at some debug log lines below. Those were generated on my Amstrad Delta videophone, using an application (asterisk softpbx with alsa channel) that can restart a receiver of a prevoiusly requested McBSP by calling omap_mcbsp_start() on user request. As you can see, corrupted values can happen to get read from any register that is expected to return predictable results.
Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: **** McBSP1 regs **** Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: DRR2: 0x1000 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: DRR1: 0x009d Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: DXR2: 0x3000 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: DXR1: 0x7da1 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: SPCR2: 0x02f0 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: SPCR1: 0x7031 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: RCR2: 0x0045 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: RCR1: 0x0040 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: XCR2: 0x1045 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: XCR1: 0x0040 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: SRGR2: 0x310f Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: SRGR1: 0x0000 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: PCR0: 0x0003 Sep 4 08:21:17 amsdelta user.debug kernel: [309910.170000] omap-mcbsp omap-mcbsp.1: mcbsp: *********************** Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: **** McBSP1 regs **** Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: DRR2: 0x0000 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: DRR1: 0x1086 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: DXR2: 0x0000 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: DXR1: 0x7da1 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: SPCR2: 0x02f0 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: SPCR1: 0x0031 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: RCR2: 0x1045 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: RCR1: 0x1040 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: XCR2: 0x3045 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: XCR1: 0x1040 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: SRGR2: 0x000f Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: SRGR1: 0x0000 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: PCR0: 0x1003 Sep 4 08:21:19 amsdelta user.debug kernel: [309912.050000] omap-mcbsp omap-mcbsp.1: mcbsp: *********************** Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: **** McBSP1 regs **** Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: DRR2: 0x1000 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: DRR1: 0x109e Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: DXR2: 0x1000 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: DXR1: 0x7da1 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: SPCR2: 0x02f0 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: SPCR1: 0x1031 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: RCR2: 0x1045 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: RCR1: 0x1040 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: XCR2: 0x2045 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: XCR1: 0x1040 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: SRGR2: 0x100f Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: SRGR1: 0x1000 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: PCR0: 0x2003 Sep 4 08:21:21 amsdelta user.debug kernel: [309913.950000] omap-mcbsp omap-mcbsp.1: mcbsp: ***********************
Those corruptions, even if should never happen, were actually caused by a wireless adapter connected to the machine USB port. Extra piece of hardware, very usefull in some cases, but obviously not taken into account while the machine was being designed. While playback seems unaffected, WiFi noise in capture stream prevents from using the videophone in speakerphone mode, but in normal (handset) mode, the noise level seems still acceptable. The only missing piece of a puzzle is my patch, that prevents the kernel driver from putting corrupted values into the McBSP control registers.
That learned, please reconsider: 1. Can my patch break anything, related or not? 2. How does it affect performance of otherwise unaffected machines? 3. Is correcting a poorly designed machine behaviour worth of the change?
Thanks, Janusz