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  1. 03 2月, 2012 5 次提交
    • J
      USB: serial, use tty_standard_install · 76f82a7a
      由 Jiri Slaby 提交于 
      But before that we need to reorder the calls so that we don't need to
lower the reference counts if usb_autopm_get_interface fails.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      76f82a7a
    • J
      TTY: provide tty_standard_install helper · 66d450e8
      由 Jiri Slaby 提交于 
      There are currently many cut&paste copies of what
tty_driver_install_tty does when custom ->install method is not
provided. Let's get rid of the copies and create a helper with this
setup code.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Havard Skinnemoen <hskinnemoen@google.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      66d450e8
    • P
      tty: serial: omap-serial: wakeup latency constraint is in microseconds, not milliseconds · 6bbcbf22
      由 Paul Walmsley 提交于 
      The receive FIFO wakeup latency estimate in the omap-serial driver is
three orders of magnitude too small.  This effectively prevents the
MPU from going to a low-power state when CONFIG_CPU_IDLE=y.  This is a
major power management regression and masks some other FIFO-related
bugs in the driver.

Fix by correcting the most egregious problem in the RX wakeup latency
estimate.  There are several other flaws in the estimator; these will
be fixed by a separate patch series intended for 3.4.

The difference in low-power states with this patch can be observed via
debugfs in pm_debug/count.

This estimate does not have any effect when CONFIG_CPU_IDLE=n.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: NGovindraj.R <govindraj.raja@ti.com>
Reviewed-by: NKevin Hilman <khilman@ti.com>
Tested-by: NKevin Hilman <khilman@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6bbcbf22
    • P
      tty: serial: OMAP: block idle while the UART is transferring data in PIO mode · edbe5dbe
      由 Paul Walmsley 提交于 
      Prevent OMAP UARTs from going idle while they are still transferring
data in PIO mode.  This works around an oversight in the OMAP UART
hardware present in OMAP34xx and earlier: an idle UART won't send a
wakeup when the TX FIFO threshold is reached.  This causes long delays
during data transmission when the MPU powerdomain enters a low-power
mode.  The MPU interrupt controller is not able to respond to
interrupts when it's in a low-power state, so the TX buffer is not
refilled until another wakeup event occurs.

This fix changes the erratum i291 DMA idle workaround.  Rather than
toggling between force-idle and no-idle, it will toggle between
smart-idle and no-idle.  The important part of the workaround is the
no-idle part, so this shouldn't result in any change in behavior.

This fix should work on all OMAP UARTs.  Future patches intended for
the 3.4 merge window will make this workaround conditional on a
"feature" flag, and will use the OMAP36xx+ TX event wakeup support.

Thanks to Kevin Hilman <khilman@ti.com> for mentioning the erratum i291
workaround, which led to the development of this approach.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: NGovindraj.R <govindraj.raja@ti.com>
Reviewed-by: NKevin Hilman <khilman@ti.com>
Tested-by: NKevin Hilman <khilman@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      edbe5dbe
    • P
      tty: serial: OMAP: use a 1-byte RX FIFO threshold in PIO mode · 5816269e
      由 Paul Walmsley 提交于 
      In the (default) PIO mode, use a one-byte RX FIFO threshold.  The OMAP
UART IP blocks do not appear to be capable of waking the system under
an RX timeout condition.  Since the previous RX FIFO threshold was 16
bytes, this meant that omap-serial.c did not become aware of any
received data until all those bytes arrived or until another UART
interrupt occurred.  This made the serial console and presumably other
serial applications (GPS, serial Bluetooth) unusable or extremely
slow.  A 1-byte RX FIFO threshold also allows the MPU to enter a
low-power consumption state while waiting for the FIFO to fill.

This can be verified using the serial console by comparing the
behavior when "0123456789abcde" is pasted in from another window, with
the behavior when "0123456789abcdef" is pasted in.  Since the former
string is less than sixteen bytes long, the string is not echoed for
some time, while the latter string is echoed immediately.

DMA operation is unaffected by this patch.

Thanks to Russell King - ARM Linux <linux@arm.linux.org.uk> for some
additional information on the standard behavior of the RX timeout
event, which was used to improve this commit description.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Govindraj Raja <govindraj.r@ti.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: NKevin Hilman <khilman@ti.com>
Tested-by: NKevin Hilman <khilman@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      5816269e
  3. 27 1月, 2012 2 次提交
  5. 25 1月, 2012 2 次提交
  7. 19 1月, 2012 4 次提交
  9. 18 1月, 2012 27 次提交