system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-11-05 18:23:50 +00:00
Code Issues Projects Releases Packages Wiki Activity
linux/drivers/tty
History
Tomoya MORINAGA 90f04c2926 pch_uart: Fix DMA resource leak issue 
Changing UART mode PIO->DMA->PIO->DMA like below, pch_uart driver can't get
DMA channel resource.

setserial /dev/ttyPCH0 ^low_latency
setserial /dev/ttyPCH0 low_latency

CAUSE:
Changing mode using setserial command, ".startup" function which gets DMA
channel is called before ".verify_port" function which sets
dma-flag(use_dma/use_dma_flag) as 1.

PIO->DMA
  .startup: Since dma-flag is 0, DMA channel is not requested.
  .verify_port: dma-flag is set as 1.
  .shutdown: N/A

DMA->PIO
  .startup: Since dma-flag is 1, DMA channel is requested.
  .verify_port: dma-flag is set as 0.
  .shutdown: Since dma-flag is 0, DMA channel is not released.

This means DMA channel resource leak occurs.
Next time, this driver can't get DMA channel resource forever.

MODIFICATION:
  Currently, when release DMA channel resource, this driver checks dma-flag.
  However, this specification occurs the above issue.
  This driver must check whether dma_request_channel is executed or not.
  The values are saved in private data variable "chan_tx/chan_tx".
  These variables mean if the value is NULL, DMA channel is not requested,
  if not NULL, DMA channel is requested.

This patch fixes the issue.

Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-11-15 12:13:43 -08:00
..
hvc tty: hvc_dcc: Fix duplicate character inputs 2011-11-15 12:02:13 -08:00
ipwireless Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2011-05-24 13:28:35 -07:00
serial pch_uart: Fix DMA resource leak issue 2011-11-15 12:13:43 -08:00
vt tty: Add export.h for EXPORT_SYMBOL/THIS_MODULE to exporters 2011-10-31 19:31:28 -04:00
amiserial.c TTY: irq: Remove IRQF_DISABLED 2011-09-22 16:08:57 -07:00
bfin_jtag_comm.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
cyclades.c TTY: irq: Remove IRQF_DISABLED 2011-09-22 16:08:57 -07:00
ehv_bytechan.c drivers/tty: don't use the byte channel handle as a parameter in ehv_bytechan.c 2011-09-26 16:38:43 -07:00
isicom.c TTY: irq: Remove IRQF_DISABLED 2011-09-22 16:08:57 -07:00
Kconfig Merge branch 'for-linus' of git://github.com/richardweinberger/linux 2011-11-02 09:45:39 -07:00
Makefile tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver 2011-08-23 10:32:56 -07:00
moxa.c drivers/tty: use printk_ratelimited() instead of printk_ratelimit() 2011-07-01 15:35:45 -07:00
moxa.h
mxser.c TTY: mxser+cyclades remove wait_until_sent debug code 2011-08-23 10:34:07 -07:00
mxser.h Fix common misspellings 2011-03-31 11:26:23 -03:00
n_gsm.c tty/n_gsm: avoid fifo overflow in gsm_dlci_data_output 2011-09-26 16:39:23 -07:00
n_hdlc.c Revert "tty: make receive_buf() return the amout of bytes received" 2011-06-04 06:33:24 +09:00
n_r3964.c Revert "tty: make receive_buf() return the amout of bytes received" 2011-06-04 06:33:24 +09:00
n_tracerouter.c n_tracerouter and n_tracesink ldisc additions. 2011-05-13 16:31:00 -07:00
n_tracesink.c n_tracerouter and n_tracesink ldisc additions. 2011-05-13 16:31:00 -07:00
n_tracesink.h n_tracerouter and n_tracesink ldisc additions. 2011-05-13 16:31:00 -07:00
n_tty.c Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6 2011-07-25 23:09:27 -07:00
nozomi.c Merge branch 'trivial' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6 2011-05-26 13:19:00 -07:00
pty.c Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty 2011-10-26 15:11:09 +02:00
rocket.c atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
rocket.h
rocket_int.h
synclink.c drivers/tty/synclink: remove double comment 2011-08-23 10:32:56 -07:00
synclink_gt.c Fix common misspellings 2011-03-31 11:26:23 -03:00
synclinkmp.c TTY: snyclinkmp: forever loop in tx_load_dma_buffer() 2011-09-29 13:23:33 -07:00
sysrq.c lib, arch: add filter argument to show_mem and fix private implementations 2011-03-24 17:49:37 -07:00
tty_audit.c
tty_buffer.c tty_buffer: get rid of 'seen_tail' logic in flush_to_ldisc 2011-06-08 07:46:30 -07:00
tty_io.c Merge branch 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty 2011-10-26 15:11:09 +02:00
tty_ioctl.c tty: Support compat_ioctl get/set termios_locked 2011-10-18 14:17:11 -07:00
tty_ldisc.c TTY: remove tty_locked 2011-08-23 10:34:07 -07:00
tty_mutex.c TTY: remove tty_locked 2011-08-23 10:34:07 -07:00
tty_port.c TTY: use tty_wait_until_sent_from_close in tty_port_close_start 2011-08-25 09:00:41 -07:00