Hi, On Mon, Jul 09 2012, Jaehoon Chung wrote: > On 07/09/2012 11:48 AM, Chris Ball wrote: > >> Hi, >> >> On Sun, Jul 08 2012, Jaehoon Chung wrote: >>>> I think MMC_CAP2_BKOPS should be removed. If the card BKOPs were already >>>> enabled, the host must support BKOPs. Therefore, in mmc_start_bkops we >>>> should check only if card->ext_csd.bkops_en is set. >>> >>> If bkops bit is set, it means that use the bkops by default. >>> If somebody didn't want to use the bkops, then just didn't set the MMC_CAP2_BKOPS. >>> And eMMC card's BKOPS bit should not be set, >>> then we can set the BKOPS support with switch command. >>> For this, MMC_CAP2_INIT_BKOPS is added. >>> In my case, didn't set the bkops enable bit at first time. >>> So need to set bkops enable bit with switch command. >>> >>> As Maya's mentioned, if we use the bkops by default, we can remove >>> the MMC_CAP2_BKOPS2. >> >> I'm not sure I understand. If someone has advertised MMC_CAP2_BKOPS on >> their host, why do we also need to check for MMC_CAP2_INIT_BKOPS before >> we enable it in the ext_csd? > > Actually, it didn't need to check the MMC_CAP2_INIT_BKOPS. > Because, if MMC_CAP2_BKOPS is set, it means we want to use the bkops. > Then we could enable in ext_csd by default. > In the initial version, didn't add the MMC_CAP2_INIT_BKOPS. > But some people asked me that card didn't set bkops enable bit in > ext_csd why set enable bkops by default? > Also others suggested the bkops enable bit should be set at user space. Oh! I'd missed that BKOPS_EN is a one-time programmable flag; sorry. In that case, Sebastian's previous review comments were correct, and you should not be touching the fuse on BKOPS_EN inside the kernelspace driver. It should only be modified from an explicit command inside mmc-utils. So, please have the kernel patch only bring up bkops if the flag is already set in the ext_csd, and please submit a userspace patch to mmc-utils for a command that sets the flag. Thanks, - Chris. -- Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/> One Laptop Per Child -- 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
