-----Original Message----- From: Pierre-Louis Bossart [mailto:pierre-louis.bossart@linux.intel.com] Sent: Tuesday, November 14, 2017 10:20 PM To: Keyon Jie yang.jie@linux.intel.com; sound-open-firmware@alsa- project.org; Girdwood, Liam R liam.r.girdwood@intel.com Cc: Jie, Yang yang.jie@intel.com Subject: Re: [Sound-open-firmware] [PATCH] intel-ipc: fix host ring buffer size not page aligned issue
On 11/14/17 12:15 AM, Keyon Jie wrote:
The host ring buffer size may be not page aligned, but the last page was ulitlized by host component
utilized
wrongly, which may introduce beating noise.
Here change to correct size for the last element, which will fix the issue.
That is plausible, I did notice an audible change when playing with the period size, but...
Signed-off-by: Keyon Jie yang.jie@linux.intel.com
src/ipc/intel-ipc.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/src/ipc/intel-ipc.c b/src/ipc/intel-ipc.c index 56bd8ba..2e503e1 100644 --- a/src/ipc/intel-ipc.c +++ b/src/ipc/intel-ipc.c @@ -192,6 +192,17 @@ static int parse_page_descriptors(struct intel_ipc_data
*iipc,
else elem.dest = phy_addr;
if (elem.size * (i + 1) >= ring->size) {/* the last page may be not full used */if (i == (ring->pages - 1))elem.size = ring->size - elem.size * i;...this code looks error-prone. should we invert the cases and test first if this is the last page? actually do you even need the first test?
Here I suppose the ring->size from host is suspect, e.g. it tells the ring->pages is 16, with the ring->size is only 3 pages.
But you are right, let me make this test more readable, and send v2.
Thanks, ~Keyon
else {trace_ipc_error("eBs");/* should not happen*/return -EINVAL;}}- if (is_trace) err = dma_trace_host_buffer(d, &elem, ring->size); else