linux/drivers/staging/comedi
Bernd Porr 5618332e5b staging: comedi: usbduxfast: usbduxfast_ai_cmdtest rounding error
The userspace comedilib function 'get_cmd_generic_timed' fills
the cmd structure with an informed guess and then calls the
function 'usbduxfast_ai_cmdtest' in this driver repeatedly while
'usbduxfast_ai_cmdtest' is modifying the cmd struct until it
no longer changes. However, because of rounding errors this never
converged because 'steps = (cmd->convert_arg * 30) / 1000' and then
back to 'cmd->convert_arg = (steps * 1000) / 30' won't be the same
because of rounding errors. 'Steps' should only be converted back to
the 'convert_arg' if 'steps' has actually been modified. In addition
the case of steps being 0 wasn't checked which is also now done.

Signed-off-by: Bernd Porr <mail@berndporr.me.uk>
Cc: <stable@vger.kernel.org> # 4.4+
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20191118230759.1727-1-mail@berndporr.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-22 11:32:54 +01:00
..
drivers staging: comedi: usbduxfast: usbduxfast_ai_cmdtest rounding error 2019-11-22 11:32:54 +01:00
kcomedilib staging: add missing SPDX lines to Makefile files 2019-04-03 11:10:15 +02:00
comedi_buf.c staging: comedi: use dma_mmap_coherent for DMA-able buffer mmap 2019-06-26 09:32:13 +08:00
comedi_compat32.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
comedi_compat32.h Staging: comedi: comedi_compat32.h: fixed missing or malformed SPDX-License-Identifier 2018-06-18 10:55:11 +02:00
comedi_fops.c staging: comedi: use dma_mmap_coherent for DMA-able buffer mmap 2019-06-26 09:32:13 +08:00
comedi_internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
comedi_pci.c staging: comedi: Remove redundant license text 2017-11-28 13:20:46 +01:00
comedi_pci.h Staging: comedi: comedi_pci.h: fixed missing or malformed SPDX-License-Identifier 2018-06-18 10:55:11 +02:00
comedi_pcmcia.c staging: comedi: Remove redundant license text 2017-11-28 13:20:46 +01:00
comedi_pcmcia.h Staging: comedi: comedi_pcmcia.h: fixed missing or malformed SPDX-License-Identifier 2018-06-18 10:55:11 +02:00
comedi_usb.c staging: comedi: Remove redundant license text 2017-11-28 13:20:46 +01:00
comedi_usb.h staging: comedi: comedi_usb.h: SPDX License Identifier is added in the first line 2018-05-31 19:00:53 +02:00
comedi.h staging: comedi: clarify/unify macros for NI macro-defined terminals 2018-11-07 13:08:28 +01:00
comedidev.h staging: comedi: ni_mio_common: Fix divide-by-zero for DIO cmdtest 2019-03-18 07:57:58 +01:00
comedilib.h Staging: comedi: comedilib.h: fixed missing or malformed SPDX-License-Identifier 2018-06-18 10:55:11 +02:00
drivers.c staging: comedi: Add lockdep_assert_held() calls for dev->attach_lock 2019-04-19 14:33:41 +02:00
Kconfig staging: comedi: use help instead of ---help--- in Kconfig 2019-04-19 15:01:50 +02:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
proc.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
range.c staging: comedi: Remove redundant license text 2017-11-28 13:20:46 +01:00
TODO