diff --git a/sys/dev/mmc/mmc_subr.c b/sys/dev/mmc/mmc_subr.c --- a/sys/dev/mmc/mmc_subr.c +++ b/sys/dev/mmc/mmc_subr.c @@ -193,7 +193,7 @@ 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 @@ */ 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)