[Description written by Alan Stern]
Soeren tracked down a very difficult bug in ehci-hcd's DMA pool
management of iTD and siTD structures. Some background: ehci-hcd
gives each isochronous endpoint its own set of active and free itd's
(or sitd's for full-speed devices). When a new itd is needed, it is
taken from the head of the free list, if possible. However, itd's
must not be used twice in a single frame because the hardware
continues to access the data structure for the entire duration of a
frame. Therefore if the itd at the head of the free list has its
"frame" member equal to the current value of ehci->now_frame, it
cannot be reused and instead a new itd is allocated from the DMA pool.
The entries on the free list are not released back to the pool until
the endpoint is no longer in use.
The bug arises from the fact that sometimes an itd can be moved back
onto the free list before itd->frame has been set properly. In
Soeren's case, this happened because ehci-hcd can allocate one more
itd than it actually needs for an URB; the extra itd may or may not be
required depending on how the transfer aligns with a frame boundary.
For example, an URB with 8 isochronous packets will cause two itd's to
be allocated. If the URB is scheduled to start in microframe 3 of
frame N then it will require both itds: one for microframes 3 - 7 of
frame N and one for microframes 0 - 2 of frame N+1. But if the URB
had been scheduled to start in microframe 0 then it would require only
the first itd, which could cover microframes 0 - 7 of frame N. The
second itd would be returned to the end of the free list.
The itd allocation routine initializes the entire structure to 0, so
the extra itd ends up on the free list with itd->frame set to 0
instead of a meaningful value. After a while the itd reaches the head
of the list, and occasionally this happens when ehci->now_frame is
equal to 0. Then, even though it would be okay to reuse this itd, the
driver thinks it must get another itd from the DMA pool.
For as long as the isochronous endpoint remains in use, this flaw in
the mechanism causes more and more itd's to be taken slowly from the
DMA pool. Since none are released back, the pool eventually becomes
exhausted.
This reuslts in memory allocation failures, which typically show up
during a long-running audio stream. Video might suffer the same
effect.
The fix is very simple. To prevent allocations from the pool when
they aren't needed, make sure that itd's sent back to the free list
prematurely have itd->frame set to an invalid value which can never be
equal to ehci->now_frame.
This should be applied to -stable kernels going back to 3.6.
Signed-off-by: Soeren Moch <smoch@web.de>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This macro relies on a local variable having a specific name. Replace
it with a new helper function, s626_mc_disable().
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This macro relies on a local variable having a specific name. Replace
it with a new helper function, s626_mc_enable().
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently the unused s626_ai_rinsn() function is commented out with
/* ... */ on every line of the function. Remove those by using an
This block will be removed once it is determined that it really
is not needed.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reformat the whitespace in the comedi_lrange table and use the
BIP_RANGE() macro instead of generic RANGE() macro.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Factor the code that handles the counter interrupt out of s626_irq_handler().
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Factor the code that handles the end of scan interrupt out of
s626_irq_handler().
Remove the printk noise when cfc_write_to_buffer() fails. The user
can't do anything about it anyway.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The comedi_async pointer is used a number of times in this function.
For aesthetic reasons, use a local variable for the pointer.
Also, since was already have a pointer to the "cmd" use that in the
for loop instead of s->async->cmd (or even async->cmd).
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The comedi_subdevice in this function is actually the dev->read_subdev
that was initialized during the attach of the board. Use that instead
of accessing the dev->subdevices array directly.
Also, get the comedi_cmd used in s626_irq_handler() when the function
is first entered.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Factor the code that checks and handles the dio interrupts out of
s626_irq_handler().
This allows reducing the number of indents in the code and makes it
easier to follow.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This driver has three dio subdevices, each with 16 channels. These
subdevices use hardware registers that are spaced 0x10 bytes apart
for each "group" of 16 channels.
Create new macros to get the correct addresses for each register
based on the dio "group". Use the s->private (void *) to hold the
"group" number to use in the subdevice functions.
This allows removing struct dio_private and all its uses. It also
removes the ugly casts used to get the register address.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The comedi core expects the (*insn_read) operations to read insn->n
values and return the number of values actually read.
Make this function work like the core expects.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a simple true/false test, return bool instead of int.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The (*do_cmdtest) already validated the cmd sources so the default
cases in the switch() statements can never happen.
Preclear to trigger bits and change the switch() statements to simple
if() tests to set the bits.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove the kernel noise in labpc_common_attach() as well as a couple
obvious comments.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
DMA support only works if an interrupt is available.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the dma channel is not available this driver will still work
with interrupts for the analog input subdevice command support.
In addition, only dma channels 1 and 3 are valid for the ISA
devices.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the interrupt is not available this driver will still work
with command support disabled for the analog input subdevice.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Make sure labpc_counter_set_mode() was successfull and return any
errno back to the caller.
For the if/else conditions that either load the counter of just set
the mode, use a common error patch to check for the error.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For aesthetic reasons, move the labpc_counter_load() function so
it's by the labpc_counter_set_mode() function.
Update all the labpc_counter_load() calls so that the I8254_MODE*
enums are used instead of the open coded values.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce labpc_counter_set_mode() which is a wrapper around the
i8254_set_mode() helpers to program the 8254 timers. Use the new
function instead of directly writing to the timer mode register
with a "magic" number.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Let the compiler figure out if this function should be inlined.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For aesthetic reasons, move a couple of the #defines in this file
so that the register map defines are first.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rename the register map defines to better match the National
Instruments Register-Level Programming Manual for the labpc.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Clean up the multi-line comments at the beginning of the file
so that they follow the CodingStyle.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix a checkpatch.pl warning about a line over 80 characters.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce a helper function to wait for the a/d conversion to
complete.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce a helper function to read the a/d conversion result
from the fifo.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce a helper function to set the COMMAND6_REG.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The labpc_cancel() function can be used by the labpc_ai_insn_read() and
labpc_ai_cmd() functions to disable the ai subdevice.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce a helper function to set the channel and gain bits in the
COMMAND1_REG.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Determine the chan, range, and aref when the variables are declared.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Determine the scan_mode early and get the proper chanspec so that
the chan, range, and aref can be determined when the variables are
declared.
labpc_ai_chanlist_invalid() checks that all the range and aref values
in the chanlist are the same so, for consistency, use the same chanspec
used to get the chan.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The ai subdevice (*do_cmd) pointer is only initialized if the
driver has successfully requested the interrupt. The extra test
in labpc_ai_cmd() is not necessary.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In labpc_ai_cmd(), move the declaration of the local variable
'irq_flags' to remove the need for the extra #ifdef/#endif.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove the DRV_NAME define and just open code the string in the
comedi_driver and pci_driver declarations.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In labpc_common_attach(), initialize the dev->board_name early and
use that instead of DRV_NAME when allocating the resources.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In labpc_common_attach(), move the declaration of the local variable
'dma_flags' to remove the need for the extra #ifdef/#endif.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add some whitespace to the subdevice init.
Remove the unnecessary comment about adding command support to
the analog input subdevice and change the 'maxdata' value to hex
as this is more common in comedi drivers.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The subdev_8255_init() function can fail. Check for failure and
return the errno.
Consolidate the mmio/ioport calls to subdev_8255_init(). The callback
function can be added with a simple ? : test and the cast of the iobase
is not necessary.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
An interrupt is required for command support to work with the
analog input subdevice. When used with the ISA driver, enabling
the interrupt is optional. Fix the subdevice init so that command
support is only enabled if the irq is available.
Add some whitespace to the subdevice init. Change the 'maxdata'
value to hex as this is more common in comedi drivers.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For aesthetic reasons, and to make grepping easier, rename all the
subdevice (*insn_read) and (*insn_write) functions.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce a helper function to determine if a range selection is
bipolar or unipolar.
This allows removing the static data 'labpc_range_is_unipolar' and
'labpc_plus_is_unipolar' as well as the boardinfo 'ai_range_is_unipolar'.
For consistency, also use the helper in labpc_ao_winsn() when
checking the range.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For aesthetic reasons, rename the local variable 'thisboard' to
'board'.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tidy up all the tables used to indicate the bipolar/unipolar
type of the range. the gain bits used to set the range, and the
comedi_lrange.
Remove a couple unnecessary #define's used to indicate the size
of the tables as well as some unnecessary comments.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For aesthetic reasons, rename the 'command*_bits' and 'status*_bits'
variables in the private data in order to shorten some of the long
lines.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As indicated by checkpatch.pl, "WARNING: Use of volatile is usually
wrong: ...". The variables in the private data that are marked
volatile don't need to be. Remove the volatile.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For aesthetic reasons, add some whitespace to the boardinfo.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This driver uses the comedi auto config mechanism to attach to PCI
boards. The "dummy" entry in the boardinfo table is not needed.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
