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restore large xfer workaround

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sadly, it's not possible to gracefully switch from large to blocked
xfers, further xfer ioctls fail after the first large xfer fails.
This commit is contained in:
Jeff Epler 2025-03-17 10:29:45 -05:00
parent fc7295eb74
commit 89dd515ae5
1 changed files with 41 additions and 5 deletions
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46
src/include/piomatter/piomatter.h
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@ -12,6 +12,42 @@
namespace piomatter {
static int pio_sm_xfer_data_large(PIO pio, int sm, int direction, size_t size,
uint32_t *databuf) {
#if 0
// it would be NICE to gracefully fall back to blocked transfer, but sadly
// once the large xfer ioctl fails, future small xfers fail too.
static enum { UNKNOWN, OK, BAD } large_xfer_status = UNKNOWN;
printf("large_xfer_status=%d\n", large_xfer_status);
if (large_xfer_status != BAD) {
int r = pio_sm_xfer_data(pio, sm, direction, size, databuf);
if (large_xfer_status == UNKNOWN && r != 0) {
large_xfer_status = BAD;
fprintf(stderr,
"Transmission limit workaround engaged. May reduce quality of "
"output.\nSee https://github.com/raspberrypi/utils/issues/123 "
"for details.\n");
} else {
if (large_xfer_status == UNKNOWN && r == 0) {
large_xfer_status = OK;
}
return r;
}
}
#endif
constexpr size_t MAX_XFER = 65532;
while (size) {
size_t xfersize = std::min(size_t{MAX_XFER}, size);
int r = pio_sm_xfer_data(pio, sm, direction, xfersize, databuf);
if (r != 0) {
return r;
}
size -= xfersize;
databuf += xfersize / sizeof(*databuf);
}
return 0;
}
static uint64_t monotonicns64() {
struct timespec tp;
clock_gettime(CLOCK_MONOTONIC, &tp);
@ -181,12 +217,12 @@ struct piomatter : piomatter_base {
auto dataptr = const_cast<uint32_t *>(&data[0]);
// returns err = rp1_ioctl.... which seems to be a negative
// errno value
int r =
pio_sm_xfer_data(pio, sm, PIO_DIR_TO_SM, datasize, dataptr);
int r = pio_sm_xfer_data_large(pio, sm, PIO_DIR_TO_SM, datasize,
dataptr);
if (r != 0) {
pending_error_errno.store(-r);
printf("xfer_data() returned error %d (%s)\n", r,
strerror(-r));
pending_error_errno.store(errno);
printf("xfer_data() returned error %d (errno=%s)\n", r,
strerror(errno));
}
t1 = monotonicns64();
if (t0 != t1) {