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Groups > linux.kernel > #1675836

[PATCH 4.9 40/44] dmaengine: bcm2835: Fix cyclic DMA period splitting

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4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Matthias Reichl <hias@horus.com>

commit 2201ac6129fa162ac24da089a034bb0971648ebb upstream.

The code responsible for splitting periods into chunks that
can be handled by the DMA controller missed to update total_len,
the number of bytes processed in the current period, when there
are more chunks to follow.

Therefore total_len was stuck at 0 and the code didn't work at all.
This resulted in a wrong control block layout and audio issues because
the cyclic DMA callback wasn't executing on period boundaries.

Fix this by adding the missing total_len update.

Signed-off-by: Matthias Reichl <hias@horus.com>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Tested-by: Clive Messer <clive.messer@digitaldreamtime.co.uk>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/dma/bcm2835-dma.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -251,8 +251,11 @@ static void bcm2835_dma_create_cb_set_le
 	 */
 
 	/* have we filled in period_length yet? */
-	if (*total_len + control_block->length < period_len)
+	if (*total_len + control_block->length < period_len) {
+		/* update number of bytes in this period so far */
+		*total_len += control_block->length;
 		return;
+	}
 
 	/* calculate the length that remains to reach period_length */
 	control_block->length = period_len - *total_len;

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[PATCH 4.9 00/44] 4.9.35-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 16/44] HID: Add quirk for Dell PIXART OEM mouse Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 14/44] CIFS: Improve readdir verbosity Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 42/44] net: phy: fix marvell phy status reading Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 10/44] perf/x86/intel: Add 1G DTLB load/store miss support for SKL Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 07/44] powerpc/perf: Fix oops when kthread execs user process Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 11/44] KVM: s390: gaccess: fix real-space designation asce handling for gmap shadows Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 21/44] brcmfmac: add parameter to pass error code in firmware callback Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 37/44] usb: gadget: f_fs: avoid out of bounds access on comp_desc Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 15/44] cxgb4: notify uP to route ctrlq compl to rdma rspq Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:20 +0200
  [PATCH 4.9 35/44] of: Add check to of_scan_flat_dt() before accessing initial_boot_params Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 06/44] fs/exec.c: account for argv/envp pointers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 27/44] target: Fix kref->refcount underflow in transport_cmd_finish_abort Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 12/44] KVM: PPC: Book3S HV: Preserve userspace HTM state properly Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 03/44] xen-blkback: dont leak stack data via response ring Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 09/44] lib/cmdline.c: fix get_options() overflow while parsing ranges Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 23/44] brcmfmac: unbind all devices upon failure in firmware callback Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 38/44] rt2x00: avoid introducing a USB dependency in the rt2x00lib module Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 28/44] iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 05/44] ALSA: pcm: Dont treat NULL chmap as a fatal error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 30/44] drm/radeon: add a PX quirk for another K53TK variant Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 26/44] arm64/vdso: Fix nsec handling for CLOCK_MONOTONIC_RAW Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 22/44] brcmfmac: use firmware callback upon failure to load Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 04/44] ALSA: firewire-lib: Fix stall of process context at packet error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 08/44] autofs: sanity check status reported with AUTOFS_DEV_IOCTL_FAIL Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 40/44] dmaengine: bcm2835: Fix cyclic DMA period splitting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 31/44] drm/radeon: add a quirk for Toshiba Satellite L20-183 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 19/44] powerpc/64s: Handle data breakpoints in Radix mode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 39/44] net: phy: Initialize mdio clock at probe function Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 25/44] time: Fix CLOCK_MONOTONIC_RAW sub-nanosecond accounting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 29/44] iscsi-target: Reject immediate data underflow larger than SCSI transfer length Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:40 +0200
  [PATCH 4.9 20/44] Input: i8042 - add Fujitsu Lifebook AH544 to notimeout list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:50 +0200
  [PATCH 4.9 18/44] powerpc/kprobes: Pause function_graph tracing during jprobes handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 16:50 +0200
  Re: [PATCH 4.9 00/44] 4.9.35-stable review Sumit Semwal <sumit.semwal@linaro.org> - 2017-06-27 19:40 +0200
    Re: [PATCH 4.9 00/44] 4.9.35-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-28 14:10 +0200
  Re: [PATCH 4.9 00/44] 4.9.35-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-27 20:40 +0200
  Re: [PATCH 4.9 00/44] 4.9.35-stable review Guenter Roeck <linux@roeck-us.net> - 2017-06-27 21:10 +0200
  Re: [PATCH 4.9 00/44] 4.9.35-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-06-28 16:00 +0200

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