hi Chris, Ulf, According to https://www.sdcard.org/downloads/pls/simplified_specs/archive/partE1_200.pdf (section CMD52 During Data Transfer ), A card may accept CMD52 during data transfer if it supports Direct Commands (see SDC, Table 6-3). For both SD and SPI modes, if an error occurs during data transfer the SDIO card shall accept CMD52 to allow I/O abort and reset regardless of this bit value of the value of SDC. But drivers/mmc/host/sdhci.c doesn't support this mode if i didn't miss something:-) we need it now to improve he throughput of a high speed Software Digital Radio SDIO card. so we'd like to add support for it. a simple idea is 1. we need to drop this WARN_ON: 1343 static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq) 1344 { 1345 struct sdhci_host *host; 1346 int present; 1347 unsigned long flags; 1348 u32 tuning_opcode; 1349 1350 host = mmc_priv(mmc); 1351 1352 sdhci_runtime_pm_get(host); 1353 1354 present = mmc_gpio_get_cd(host->mmc); 1355 1356 spin_lock_irqsave(&host->lock, flags); 1357 1358 WARN_ON(host->mrq != NULL); 2. we need to permit a new command to execute even when host->mrq is not NULL and a CMD53 is ongoing. this means we might add a new cmd52 request field in host struct to buffer CMD52 request. and after the cmd52 finishes, we still need the capability to wake up the blocking thread. I'd like to know your suggestions on this feature. -barry -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
