diff options
| author | Austin Shafer <ashafer@badland.io> | 2021-06-03 01:46:23 +0000 |
|---|---|---|
| committer | Warner Losh <imp@FreeBSD.org> | 2021-06-03 01:46:23 +0000 |
| commit | e7dc08415a324d1000cd067fbc12b1ec79e0b2ac (patch) | |
| tree | 3df3199c246e9dd6a30dc18681ca4efcc0672038 | |
| parent | 9a0f82285322a338548d13fcda07e1d574301190 (diff) | |
| download | src-e7dc08415a324d1000cd067fbc12b1ec79e0b2ac.tar.gz src-e7dc08415a324d1000cd067fbc12b1ec79e0b2ac.zip | |
mmc: ignore CRC errors from CMD13 (status) when changing rates
Update mmc_switch_status to ignore a few CRC errrors when asking for the
card status after setting the new rate with CMD6. Since the card may
take a little while to make the switch, it's possible we'll get a
communications error if we sent the command at the wrong time. Several
low end laptops needs this workaround as they have a window that seems
longer than other systems. This is known to fix at least the Acer Aspire
A114-32-P7E5.
Reviewed by: imp@, manu@
Differential Revision: https://reviews.freebsd.org/D24740
| -rw-r--r-- | sys/dev/mmc/mmc_subr.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/sys/dev/mmc/mmc_subr.c b/sys/dev/mmc/mmc_subr.c index 53c9009c6e64..b43a233820bb 100644 --- a/sys/dev/mmc/mmc_subr.c +++ b/sys/dev/mmc/mmc_subr.c @@ -193,7 +193,7 @@ int mmc_switch_status(device_t busdev, device_t dev, uint16_t rca, u_int timeout) { struct timeval cur, end; - int err; + int err, crc_timeout; uint32_t status; KASSERT(timeout != 0, ("%s: no timeout", __func__)); @@ -205,7 +205,19 @@ mmc_switch_status(device_t busdev, device_t dev, uint16_t rca, u_int timeout) */ end.tv_sec = end.tv_usec = 0; for (;;) { - err = mmc_send_status(busdev, dev, rca, &status); + crc_timeout=0; + do { + /* + * CRC errors indicate that the command wasn't accepted + * and executed due to a communications error. Retry + * CRC errors a couple of times to cope with transient + * failures. + * + * This is required for some cheap laptops to boot. + */ + err = mmc_send_status(busdev, dev, rca, &status); + crc_timeout++; + } while (err == MMC_ERR_BADCRC && crc_timeout < 10); if (err != MMC_ERR_NONE) break; if (R1_CURRENT_STATE(status) == R1_STATE_TRAN) |