近期调试几款sdio card suspend时都会出现sdio card removed，之后
要么死机要么模块不能正常工作。根本原因也就是休眠没有处理好。昨天最终找到了
解决方法。
1：host端须要设置nonremovable,软件设置：mmc->caps |=
MMC_CAP_NONREMOVABLE;
2：host端须要设置keep power,在sdio card suspend时 软件设
置:host->pm_flags | = MMC_PM_KEEP_POWER；
眼下我所接触到的4g网卡,博通网卡,sdio加密t卡等都会出现card
removed问题。
关于2补充下须要在sdio card pm中置host keep power:
static int XXX_suspend(struct device *pdev)
{
struct sdio_func *func = dev_to_sdio_func(pdev); /* keep power while host suspended */
ret = sdio_set_host_pm_flags(func, MMC_PM_KEEP_POWER);
if (ret) {
sd_err(("%s: error while trying to keep power\n", __FUNCTION__));
return ret;
} return 0;
} static const struct dev_pm_ops XXX_pm_ops = {
.suspend = XXX_suspend,
.resume = XXX_resume,
};
今天花了点时间理清了card removed的原因。
出现1错误的原因是在resume 时pm_notify调用到了msm_rescan,假设没
有置nonremovable,将会跑进detect,而进去就会detect出了card removed,
进而进行了移除操作。
void mmc_rescan(struct work_struct *work)
{
struct mmc_host *host =
container_of(work, struct mmc_host, detect.work);
bool extend_wakelock = false; if (host->rescan_disable)
return; mmc_bus_get(host); /*
* if there is a _removable_ card registered, check whether it is
* still present
*/
if (host->bus_ops && host->bus_ops->detect && !host->bus_dead
&& !(host->caps & MMC_CAP_NONREMOVABLE))
host->bus_ops->detect(host);
---------
}
以下是dump_stack()打印的调用信息：
<4>[ 48.709320] [<c0013d4c>] (unwind_backtrace+0x0/0x11c) from
[<bf011d74>] (dhdsdio_disconnect+0xc/0x10c [bcmdhd])
<4>[ 48.720214] [<bf011d74>] (dhdsdio_disconnect+0xc/0x10c [bcmdhd])
from [<bf01f9a8>] (bcmsdh_remove+0x1c/0x98 [bcmdhd])
<4>[ 48.730041] [<bf01f9a8>] (bcmsdh_remove+0x1c/0x98 [bcmdhd]) from
[<bf001a00>] (bcmsdh_sdmmc_remove+0x28/0x70 [bcmdhd])
<4>[ 48.740600] [<bf001a00>] (bcmsdh_sdmmc_remove+0x28/0x70 [bcmdhd])
from [<c05855e0>] (sdio_bus_remove+0x38/0xf0)
<4>[ 48.753021] [<c05855e0>] (sdio_bus_remove+0x38/0xf0) from
[<c03a26c8>] (__device_release_driver+0x9c/0xe0)
<4>[ 48.762725] [<c03a26c8>] (__device_release_driver+0x9c/0xe0) from
[<c03a2728>] (device_release_driver+0x1c/0x28)
<4>[ 48.771881] [<c03a2728>] (device_release_driver+0x1c/0x28) from
[<c03a21f8>] (bus_remove_device+0x124/0x140)
<4>[ 48.781829] [<c03a21f8>] (bus_remove_device+0x124/0x140) from
[<c039fe30>] (device_del+0x108/0x16c)
<4>[ 48.790802] [<c039fe30>] (device_del+0x108/0x16c) from
[<c058596c>] (sdio_remove_func+0x1c/0x28)
<4>[ 48.799560] [<c058596c>] (sdio_remove_func+0x1c/0x28) from
[<c0584bfc>] (mmc_sdio_remove+0x3c/0x68)
<4>[ 48.808593] [<c0584bfc>] (mmc_sdio_remove+0x3c/0x68) from
[<c0584cb4>] (mmc_sdio_detect+0x8c/0xb4)
<4>[ 48.817565] [<c0584cb4>] (mmc_sdio_detect+0x8c/0xb4) from
[<c057e0c8>] (mmc_rescan+0x7c/0x2d8)
<4>[ 48.826141] [<c057e0c8>] (mmc_rescan+0x7c/0x2d8) from [<c0099dd8>]
(process_one_work+0x27c/0x484)
<4>[ 48.834991] [<c0099dd8>] (process_one_work+0x27c/0x484) from
[<c009a1f0>] (worker_thread+0x210/0x3b0)
<4>[ 48.844177] [<c009a1f0>] (worker_thread+0x210/0x3b0) from
[<c009e08c>] (kthread+0x80/0x8c)
<4>[ 48.852355] [<c009e08c>] (kthread+0x80/0x8c) from [<c000eaa8>]
(kernel_thread_exit+0x0/0x8)
<6>[ 49.083587] mmc2: card 0001 removed
出现2错误的原因是在sdio resume时，假设没有设置keep power就会
跑sdio reset与go idle（CMD 0）后进入init_card第一个CMD就不会响应了。也就是
这2个操作后card异常了。
static int mmc_sdio_resume(struct mmc_host *host)
{
int i, err = 0; BUG_ON(!host);
BUG_ON(!host->card); /* Basic card reinitialization. */
mmc_claim_host(host); /* No need to reinitialize powered-resumed nonremovable cards */
if (mmc_card_is_removable(host) || !mmc_card_keep_power(host)) {
sdio_reset(host);
mmc_go_idle(host);
err = mmc_sdio_init_card(host, host->ocr, host->card,
mmc_card_keep_power(host));
---------
}
下面是dump_stack()信息打印：
<4>[ 55.269378] [<c0013d4c>] (unwind_backtrace+0x0/0x11c) from
[<c057d650>] (mmc_resume_host+0xec/0x15c)
<4>[ 55.269439] [<c057d650>] (mmc_resume_host+0xec/0x15c) from
[<c058bfdc>] (msmsdcc_runtime_resume+0xb8/0x17c)
<4>[ 55.269500] [<c058bfdc>] (msmsdcc_runtime_resume+0xb8/0x17c) from
[<c058c2ac>] (msmsdcc_pm_resume+0x44/0xa8)
<4>[ 55.269561] [<c058c2ac>] (msmsdcc_pm_resume+0x44/0xa8) from
[<c03a4074>] (platform_pm_resume+0x40/0x54)
<4>[ 55.269653] [<c03a4074>] (platform_pm_resume+0x40/0x54) from
[<c03a8160>] (dpm_run_callback+0x44/0x7c)
<4>[ 55.269683] [<c03a8160>] (dpm_run_callback+0x44/0x7c) from
[<c03a8c18>] (device_resume+0x140/0x184)
<4>[ 55.269744] [<c03a8c18>] (device_resume+0x140/0x184) from
[<c03a94ec>] (dpm_resume+0xfc/0x234)
<4>[ 55.269805] [<c03a94ec>] (dpm_resume+0xfc/0x234) from [<c03a97f0>]
(dpm_resume_end+0xc/0x18)
<4>[ 55.269866] [<c03a97f0>] (dpm_resume_end+0xc/0x18) from
[<c00b63bc>] (suspend_devices_and_enter+0x240/0x314)
<4>[ 55.269927] [<c00b63bc>] (suspend_devices_and_enter+0x240/0x314)
from [<c00b65b0>] (pm_suspend+0x120/0x200)
<4>[ 55.269958] [<c00b65b0>] (pm_suspend+0x120/0x200) from
[<c00b7508>] (suspend+0x68/0x180)
<4>[ 55.270019] [<c00b7508>] (suspend+0x68/0x180) from [<c0099dd8>]
(process_one_work+0x27c/0x484)
<4>[ 55.270080] [<c0099dd8>] (process_one_work+0x27c/0x484) from
[<c009a1f0>] (worker_thread+0x210/0x3b0)
<4>[ 55.270141] [<c009a1f0>] (worker_thread+0x210/0x3b0) from
[<c009e08c>] (kthread+0x80/0x8c)
<4>[ 55.270202] [<c009e08c>] (kthread+0x80/0x8c) from [<c000eaa8>]
(kernel_thread_exit+0x0/0x8)
<4>[ 55.270233] mmc2: error -110 during resume (card was removed? )
以上2点做到了理论上kernel能够正常睡眠了，以下是正常的睡眠log:
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