[dvblast-devel] error: couldn't read from DVR device (Value too large for defined data type)

[Honza Petrouš]

2013/7/3 Georgi Chorbadzhiyski <gf at unixsol.org>:
> I'm using digital devices S2 card with these drivers on linux 3.7.1
>
> [    5.384924] Latest git patches (needed if you report a bug to linux-media at vger.kernel.org):
> [    5.384924]  8b2aea7878f64814544d0527c659011949d52358 [media] em28xx: prefer bulk mode on webcams
> [    5.384924]  a3efa1cc0e067675ffa2d2c357cbe1da0db4653b [media] em28xx: make the logs reflect the specific chip name
> [    5.384924]  aa51496b21542855e779a78bf33384002f01acb6 [media] em28xx: display the isoc/bulk mode
> [    5.384924]  experimental: 9b79c0d0acf1607158e1bdb70fe913059894bfd5 experimental: Add workaround for CAM write errors.
> [    5.384924]  ngene-octopus-test: a8742d5952072f2237cdf28ae4cbb78fa6039f80 ddbridge: Add Digital Devices Cine S2 V6.5
> [    5.414058] Digital Devices PCIE bridge driver, Copyright (C) 2010-11 Digital Devices GmbH
> [    5.414546] DDBridge driver detected: Digital Devices Cine S2 V6 DVB adapter
>
> Couple of days ago one of the transponders that I'm using began to log these errors from
> time to time:
>
> Jul  3 00:26:19 live4 dvblast/00_39_12524_H_30000_bulsat: error: couldn't read from DVR device (Value too large for defined data type)
> Jul  3 00:53:18 live4 dvblast/00_39_12524_H_30000_bulsat: error: couldn't read from DVR device (Value too large for defined data type)
> Jul  3 04:52:18 live4 dvblast/00_39_12524_H_30000_bulsat: error: couldn't read from DVR device (Value too large for defined data type)
> Jul  3 05:31:17 live4 dvblast/00_39_12524_H_30000_bulsat: error: couldn't read from DVR device (Value too large for defined data type)
> Jul  3 05:32:19 live4 dvblast/00_39_12524_H_30000_bulsat: error: couldn't read from DVR device (Value too large for defined data type)
>
> It is happening only on this transponder [1] (the machine reads 12 others as well but
> they are fine). What could possibly be the reason? Is it too much data coming and the
> driver can't handle it? If I lower down MAX_READ_ONCE could this help?

Yes, it happens when kernel's dvb ringbuffer gets overwritten by too
much incomming data.
Try to change a buffer size by ioctl DMX_SET_BUFFER_SIZE.

BR.
/Honza