* [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal [not found] <CGME20260104023451epcas5p391708610b5ce46d0e2a5f4bfbad01c71@epcas5p3.samsung.com> @ 2026-01-04 2:38 ` ping.gao 2026-01-04 2:55 ` Shawn Lin 0 siblings, 1 reply; 8+ messages in thread From: ping.gao @ 2026-01-04 2:38 UTC (permalink / raw) To: jh80.chung, ulf.hansson, linux-mmc, linux-kernel; +Cc: ping.gao some vendor doesn't use biu_clk , enable it will panic log is below: [ 438.400868] [7: binder:436_2: 4998] Unable to handle kernel paging request at virtual address fffffffffffffffe [ 438.400877] [7: binder:436_2: 4998] Mem abort info: [ 438.400881] [7: binder:436_2: 4998] ESR = 0x0000000096000005 [ 438.400887] [7: binder:436_2: 4998] EC = 0x25: DABT (current EL), IL = 32 bits [ 438.400894] [7: binder:436_2: 4998] SET = 0, FnV = 0 [ 438.400899] [7: binder:436_2: 4998] EA = 0, S1PTW = 0 [ 438.400904] [7: binder:436_2: 4998] FSC = 0x05: level 1 translation fault ... [ 438.409424] [7: binder:436_2: 4998] Call trace: [ 438.409429] [7: binder:436_2: 4998] clk_prepare+0x10/0x24 [ 438.409439] [7: binder:436_2: 4998] dw_mci_runtime_resume+0x50/0x2d8 [dw_mmc_samsung cd210e210975263404c28fc89778f369f8398f0c] [ 438.409471] [7: binder:436_2: 4998] dw_mci_exynos_runtime_resume+0x18/0x58 [dw_mmc_exynos_samsung 2735a594c7c9c9e8c65b0b87523fbf70dcaabfff] [ 438.409496] [7: binder:436_2: 4998] pm_generic_runtime_resume+0x40/0x58 [ 438.409506] [7: binder:436_2: 4998] pm_runtime_force_resume+0x9c/0x134 [ 438.409517] [7: binder:436_2: 4998] platform_pm_resume+0x40/0x8c [ 438.409529] [7: binder:436_2: 4998] dpm_run_callback+0x64/0x230 [ 438.409540] [7: binder:436_2: 4998] __device_resume+0x1d8/0x394 [ 438.409551] [7: binder:436_2: 4998] dpm_resume+0x110/0x2b8 [ 438.409561] [7: binder:436_2: 4998] dpm_resume_end+0x1c/0x38 [ 438.409570] [7: binder:436_2: 4998] suspend_devices_and_enter+0x828/0xab0 [ 438.409582] [7: binder:436_2: 4998] pm_suspend+0x334/0x618 [ 438.409592] [7: binder:436_2: 4998] state_store+0x104/0x144 [ 438.409601] [7: binder:436_2: 4998] kobj_attr_store+0x30/0x48 [ 438.409610] [7: binder:436_2: 4998] sysfs_kf_write+0x54/0x6c [ 438.409619] [7: binder:436_2: 4998] kernfs_fop_write_iter+0x104/0x1a8 [ 438.409628] [7: binder:436_2: 4998] vfs_write+0x24c/0x2f4 [ 438.409640] [7: binder:436_2: 4998] ksys_write+0x78/0xe8 [ 438.409652] [7: binder:436_2: 4998] __arm64_sys_write+0x1c/0x2c [ 438.409664] [7: binder:436_2: 4998] invoke_syscall+0x58/0x114 [ 438.409676] [7: binder:436_2: 4998] el0_svc_common+0xac/0xe0 [ 438.409687] [7: binder:436_2: 4998] do_el0_svc+0x1c/0x28 [ 438.409698] [7: binder:436_2: 4998] el0_svc+0x38/0x68 [ 438.409705] [7: binder:436_2: 4998] el0t_64_sync_handler+0x68/0xbc [ 438.409712] [7: binder:436_2: 4998] el0t_64_sync+0x1a8/0x1ac Signed-off-by: ping.gao <ping.gao@samsung.com> --- drivers/mmc/host/dw_mmc.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index c5db92bbb094..61f6986f15ef 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -3633,9 +3633,15 @@ int dw_mci_runtime_resume(struct device *dev) if (host->slot && (mmc_host_can_gpio_cd(host->slot->mmc) || !mmc_card_is_removable(host->slot->mmc))) { - ret = clk_prepare_enable(host->biu_clk); - if (ret) - return ret; + if (IS_ERR(host->biu_clk)) { + dev_dbg(host->dev, "biu clock not available\n"); + } else { + ret = clk_prepare_enable(host->biu_clk); + if (ret) { + dev_err(host->dev, "failed to enable biu clock\n"); + goto err; + } + } } ret = clk_prepare_enable(host->ciu_clk); -- 2.50.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal 2026-01-04 2:38 ` [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal ping.gao @ 2026-01-04 2:55 ` Shawn Lin 2026-01-04 6:01 ` Sebastian Reichel 0 siblings, 1 reply; 8+ messages in thread From: Shawn Lin @ 2026-01-04 2:55 UTC (permalink / raw) To: ping.gao; +Cc: shawn.lin, jh80.chung, ulf.hansson, linux-kernel, linux-mmc 在 2026/01/04 星期日 10:38, ping.gao 写道: > some vendor doesn't use biu_clk , enable it will panic > log is below: I still don't understand the real issue you tried to solve. host->biu_clk is got via devm_clk_get() in dw_mci_probe(). If succeed, immediately it's enabled a few lines below. Otherwise, dw_mci_probe() returns with failure. Seems you are not enabling it in runtime callbacks, but why clk_prepare_enable(host->biu_clk) is able to work when driver probed? > [ 438.400868] [7: binder:436_2: 4998] Unable to handle kernel paging request at virtual address fffffffffffffffe > [ 438.400877] [7: binder:436_2: 4998] Mem abort info: > [ 438.400881] [7: binder:436_2: 4998] ESR = 0x0000000096000005 > [ 438.400887] [7: binder:436_2: 4998] EC = 0x25: DABT (current EL), IL = 32 bits > [ 438.400894] [7: binder:436_2: 4998] SET = 0, FnV = 0 > [ 438.400899] [7: binder:436_2: 4998] EA = 0, S1PTW = 0 > [ 438.400904] [7: binder:436_2: 4998] FSC = 0x05: level 1 translation fault > ... > [ 438.409424] [7: binder:436_2: 4998] Call trace: > [ 438.409429] [7: binder:436_2: 4998] clk_prepare+0x10/0x24 > [ 438.409439] [7: binder:436_2: 4998] dw_mci_runtime_resume+0x50/0x2d8 [dw_mmc_samsung cd210e210975263404c28fc89778f369f8398f0c] > [ 438.409471] [7: binder:436_2: 4998] dw_mci_exynos_runtime_resume+0x18/0x58 [dw_mmc_exynos_samsung 2735a594c7c9c9e8c65b0b87523fbf70dcaabfff] > [ 438.409496] [7: binder:436_2: 4998] pm_generic_runtime_resume+0x40/0x58 > [ 438.409506] [7: binder:436_2: 4998] pm_runtime_force_resume+0x9c/0x134 > [ 438.409517] [7: binder:436_2: 4998] platform_pm_resume+0x40/0x8c > [ 438.409529] [7: binder:436_2: 4998] dpm_run_callback+0x64/0x230 > [ 438.409540] [7: binder:436_2: 4998] __device_resume+0x1d8/0x394 > [ 438.409551] [7: binder:436_2: 4998] dpm_resume+0x110/0x2b8 > [ 438.409561] [7: binder:436_2: 4998] dpm_resume_end+0x1c/0x38 > [ 438.409570] [7: binder:436_2: 4998] suspend_devices_and_enter+0x828/0xab0 > [ 438.409582] [7: binder:436_2: 4998] pm_suspend+0x334/0x618 > [ 438.409592] [7: binder:436_2: 4998] state_store+0x104/0x144 > [ 438.409601] [7: binder:436_2: 4998] kobj_attr_store+0x30/0x48 > [ 438.409610] [7: binder:436_2: 4998] sysfs_kf_write+0x54/0x6c > [ 438.409619] [7: binder:436_2: 4998] kernfs_fop_write_iter+0x104/0x1a8 > [ 438.409628] [7: binder:436_2: 4998] vfs_write+0x24c/0x2f4 > [ 438.409640] [7: binder:436_2: 4998] ksys_write+0x78/0xe8 > [ 438.409652] [7: binder:436_2: 4998] __arm64_sys_write+0x1c/0x2c > [ 438.409664] [7: binder:436_2: 4998] invoke_syscall+0x58/0x114 > [ 438.409676] [7: binder:436_2: 4998] el0_svc_common+0xac/0xe0 > [ 438.409687] [7: binder:436_2: 4998] do_el0_svc+0x1c/0x28 > [ 438.409698] [7: binder:436_2: 4998] el0_svc+0x38/0x68 > [ 438.409705] [7: binder:436_2: 4998] el0t_64_sync_handler+0x68/0xbc > [ 438.409712] [7: binder:436_2: 4998] el0t_64_sync+0x1a8/0x1ac > Signed-off-by: ping.gao <ping.gao@samsung.com> > --- > drivers/mmc/host/dw_mmc.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index c5db92bbb094..61f6986f15ef 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -3633,9 +3633,15 @@ int dw_mci_runtime_resume(struct device *dev) > if (host->slot && > (mmc_host_can_gpio_cd(host->slot->mmc) || > !mmc_card_is_removable(host->slot->mmc))) { > - ret = clk_prepare_enable(host->biu_clk); > - if (ret) > - return ret; > + if (IS_ERR(host->biu_clk)) { > + dev_dbg(host->dev, "biu clock not available\n"); > + } else { > + ret = clk_prepare_enable(host->biu_clk); > + if (ret) { > + dev_err(host->dev, "failed to enable biu clock\n"); > + goto err; > + } > + } > } > > ret = clk_prepare_enable(host->ciu_clk); ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal 2026-01-04 2:55 ` Shawn Lin @ 2026-01-04 6:01 ` Sebastian Reichel 2026-01-04 7:38 ` Shawn Lin 0 siblings, 1 reply; 8+ messages in thread From: Sebastian Reichel @ 2026-01-04 6:01 UTC (permalink / raw) To: Shawn Lin; +Cc: ping.gao, jh80.chung, ulf.hansson, linux-kernel, linux-mmc [-- Attachment #1: Type: text/plain, Size: 5572 bytes --] Hi, On Sun, Jan 04, 2026 at 10:55:48AM +0800, Shawn Lin wrote: > 在 2026/01/04 星期日 10:38, ping.gao 写道: > > some vendor doesn't use biu_clk , enable it will panic > > log is below: > > I still don't understand the real issue you tried to solve. > > host->biu_clk is got via devm_clk_get() in dw_mci_probe(). If > succeed, immediately it's enabled a few lines below. Otherwise, > dw_mci_probe() returns with failure. Seems you are not enabling it in > runtime callbacks, but why clk_prepare_enable(host->biu_clk) is able > to work when driver probed? Based on the error and this patch, I believe what happens is: 1. dw_mci_probe() calls devm_clk_get(host->dev, "biu") 2. The clock does not exist on the platform from Ping Gao, so host->biu_clk gets an error pointer assigned 3. "biu clock not available" gets printed at debug level 4. the error is ignored, but the error pointer is still assigned to host->biu_clk 5. in the runtime PM handler clk_prepare_enable is called for host->biu_clk and thus for an error pointer Instead of hacking this up even further (as this patch does), the proper fix is to cleanup the probe function. I believe the complete biu clock handling in it could be reduced to this: host->biu_clk = devm_clk_get_optional_enabled(host->dev, "biu"); ret = PTR_ERR_OR_ZERO(host->biu_clk); if (ret) return dev_err_probe(host->dev, ret, "failed to get biu clock\n"); That will assign NULL to host->biu_clk when there is no clock defined and it is fine to run clk_prepare_enable() with NULL as clock pointer. Note, that this will handle the clock enabling as part of devm, so you will also have to drop the clk_disable_unprepare() calls from the err_clk_biu goto label and the extra call from dw_mci_remove(). Something similar should probably be done for host->ciu_clk, which seems to have the same incorrect logic. Greetings, -- Sebastian > > [ 438.400868] [7: binder:436_2: 4998] Unable to handle kernel paging request at virtual address fffffffffffffffe > > [ 438.400877] [7: binder:436_2: 4998] Mem abort info: > > [ 438.400881] [7: binder:436_2: 4998] ESR = 0x0000000096000005 > > [ 438.400887] [7: binder:436_2: 4998] EC = 0x25: DABT (current EL), IL = 32 bits > > [ 438.400894] [7: binder:436_2: 4998] SET = 0, FnV = 0 > > [ 438.400899] [7: binder:436_2: 4998] EA = 0, S1PTW = 0 > > [ 438.400904] [7: binder:436_2: 4998] FSC = 0x05: level 1 translation fault > > ... > > [ 438.409424] [7: binder:436_2: 4998] Call trace: > > [ 438.409429] [7: binder:436_2: 4998] clk_prepare+0x10/0x24 > > [ 438.409439] [7: binder:436_2: 4998] dw_mci_runtime_resume+0x50/0x2d8 [dw_mmc_samsung cd210e210975263404c28fc89778f369f8398f0c] > > [ 438.409471] [7: binder:436_2: 4998] dw_mci_exynos_runtime_resume+0x18/0x58 [dw_mmc_exynos_samsung 2735a594c7c9c9e8c65b0b87523fbf70dcaabfff] > > [ 438.409496] [7: binder:436_2: 4998] pm_generic_runtime_resume+0x40/0x58 > > [ 438.409506] [7: binder:436_2: 4998] pm_runtime_force_resume+0x9c/0x134 > > [ 438.409517] [7: binder:436_2: 4998] platform_pm_resume+0x40/0x8c > > [ 438.409529] [7: binder:436_2: 4998] dpm_run_callback+0x64/0x230 > > [ 438.409540] [7: binder:436_2: 4998] __device_resume+0x1d8/0x394 > > [ 438.409551] [7: binder:436_2: 4998] dpm_resume+0x110/0x2b8 > > [ 438.409561] [7: binder:436_2: 4998] dpm_resume_end+0x1c/0x38 > > [ 438.409570] [7: binder:436_2: 4998] suspend_devices_and_enter+0x828/0xab0 > > [ 438.409582] [7: binder:436_2: 4998] pm_suspend+0x334/0x618 > > [ 438.409592] [7: binder:436_2: 4998] state_store+0x104/0x144 > > [ 438.409601] [7: binder:436_2: 4998] kobj_attr_store+0x30/0x48 > > [ 438.409610] [7: binder:436_2: 4998] sysfs_kf_write+0x54/0x6c > > [ 438.409619] [7: binder:436_2: 4998] kernfs_fop_write_iter+0x104/0x1a8 > > [ 438.409628] [7: binder:436_2: 4998] vfs_write+0x24c/0x2f4 > > [ 438.409640] [7: binder:436_2: 4998] ksys_write+0x78/0xe8 > > [ 438.409652] [7: binder:436_2: 4998] __arm64_sys_write+0x1c/0x2c > > [ 438.409664] [7: binder:436_2: 4998] invoke_syscall+0x58/0x114 > > [ 438.409676] [7: binder:436_2: 4998] el0_svc_common+0xac/0xe0 > > [ 438.409687] [7: binder:436_2: 4998] do_el0_svc+0x1c/0x28 > > [ 438.409698] [7: binder:436_2: 4998] el0_svc+0x38/0x68 > > [ 438.409705] [7: binder:436_2: 4998] el0t_64_sync_handler+0x68/0xbc > > [ 438.409712] [7: binder:436_2: 4998] el0t_64_sync+0x1a8/0x1ac > > Signed-off-by: ping.gao <ping.gao@samsung.com> > > --- > > drivers/mmc/host/dw_mmc.c | 12 +++++++++--- > > 1 file changed, 9 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > > index c5db92bbb094..61f6986f15ef 100644 > > --- a/drivers/mmc/host/dw_mmc.c > > +++ b/drivers/mmc/host/dw_mmc.c > > @@ -3633,9 +3633,15 @@ int dw_mci_runtime_resume(struct device *dev) > > if (host->slot && > > (mmc_host_can_gpio_cd(host->slot->mmc) || > > !mmc_card_is_removable(host->slot->mmc))) { > > - ret = clk_prepare_enable(host->biu_clk); > > - if (ret) > > - return ret; > > + if (IS_ERR(host->biu_clk)) { > > + dev_dbg(host->dev, "biu clock not available\n"); > > + } else { > > + ret = clk_prepare_enable(host->biu_clk); > > + if (ret) { > > + dev_err(host->dev, "failed to enable biu clock\n"); > > + goto err; > > + } > > + } > > } > > ret = clk_prepare_enable(host->ciu_clk); > > [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal 2026-01-04 6:01 ` Sebastian Reichel @ 2026-01-04 7:38 ` Shawn Lin 2026-01-04 14:48 ` Sebastian Reichel 0 siblings, 1 reply; 8+ messages in thread From: Shawn Lin @ 2026-01-04 7:38 UTC (permalink / raw) To: Sebastian Reichel Cc: shawn.lin, ping.gao, jh80.chung, ulf.hansson, linux-kernel, linux-mmc Hi Sevastian, 在 2026/01/04 星期日 14:01, Sebastian Reichel 写道: > Hi, > > On Sun, Jan 04, 2026 at 10:55:48AM +0800, Shawn Lin wrote: >> 在 2026/01/04 星期日 10:38, ping.gao 写道: >>> some vendor doesn't use biu_clk , enable it will panic >>> log is below: >> >> I still don't understand the real issue you tried to solve. >> >> host->biu_clk is got via devm_clk_get() in dw_mci_probe(). If >> succeed, immediately it's enabled a few lines below. Otherwise, >> dw_mci_probe() returns with failure. Seems you are not enabling it in >> runtime callbacks, but why clk_prepare_enable(host->biu_clk) is able >> to work when driver probed? > > Based on the error and this patch, I believe what happens is: > > 1. dw_mci_probe() calls devm_clk_get(host->dev, "biu") > 2. The clock does not exist on the platform from Ping Gao, so > host->biu_clk gets an error pointer assigned > 3. "biu clock not available" gets printed at debug level > 4. the error is ignored, but the error pointer is still assigned to > host->biu_clk > 5. in the runtime PM handler clk_prepare_enable is called for > host->biu_clk and thus for an error pointer > Thanks for the details. For example, 1. dw_mci_exynos_probe() enables runtime PM before calling dw_mci_pltfm_register()->dw_mci_probe(). 2. biu_clk gets an error and propagate it to dw_mci_pltfm_register(), 3. runtime PM is disabled in dw_mci_exynos_probe() later if seeing error. Does that mean runtime PM handler is called between step 2 and step 3? If that is the case, how could we allow this happen because the the controller's configuaration isn't been finished yet. Or maybe I misunderstand your point? > Instead of hacking this up even further (as this patch does), > the proper fix is to cleanup the probe function. I believe > the complete biu clock handling in it could be reduced to this: > > host->biu_clk = devm_clk_get_optional_enabled(host->dev, "biu"); > ret = PTR_ERR_OR_ZERO(host->biu_clk); > if (ret) > return dev_err_probe(host->dev, ret, "failed to get biu clock\n"); > > That will assign NULL to host->biu_clk when there is no clock > defined and it is fine to run clk_prepare_enable() with NULL > as clock pointer. Note, that this will handle the clock enabling > as part of devm, so you will also have to drop the > clk_disable_unprepare() calls from the err_clk_biu goto label > and the extra call from dw_mci_remove(). > > Something similar should probably be done for host->ciu_clk, which > seems to have the same incorrect logic. > > Greetings, > > -- Sebastian > >>> [ 438.400868] [7: binder:436_2: 4998] Unable to handle kernel paging request at virtual address fffffffffffffffe >>> [ 438.400877] [7: binder:436_2: 4998] Mem abort info: >>> [ 438.400881] [7: binder:436_2: 4998] ESR = 0x0000000096000005 >>> [ 438.400887] [7: binder:436_2: 4998] EC = 0x25: DABT (current EL), IL = 32 bits >>> [ 438.400894] [7: binder:436_2: 4998] SET = 0, FnV = 0 >>> [ 438.400899] [7: binder:436_2: 4998] EA = 0, S1PTW = 0 >>> [ 438.400904] [7: binder:436_2: 4998] FSC = 0x05: level 1 translation fault >>> ... >>> [ 438.409424] [7: binder:436_2: 4998] Call trace: >>> [ 438.409429] [7: binder:436_2: 4998] clk_prepare+0x10/0x24 >>> [ 438.409439] [7: binder:436_2: 4998] dw_mci_runtime_resume+0x50/0x2d8 [dw_mmc_samsung cd210e210975263404c28fc89778f369f8398f0c] >>> [ 438.409471] [7: binder:436_2: 4998] dw_mci_exynos_runtime_resume+0x18/0x58 [dw_mmc_exynos_samsung 2735a594c7c9c9e8c65b0b87523fbf70dcaabfff] >>> [ 438.409496] [7: binder:436_2: 4998] pm_generic_runtime_resume+0x40/0x58 >>> [ 438.409506] [7: binder:436_2: 4998] pm_runtime_force_resume+0x9c/0x134 >>> [ 438.409517] [7: binder:436_2: 4998] platform_pm_resume+0x40/0x8c >>> [ 438.409529] [7: binder:436_2: 4998] dpm_run_callback+0x64/0x230 >>> [ 438.409540] [7: binder:436_2: 4998] __device_resume+0x1d8/0x394 >>> [ 438.409551] [7: binder:436_2: 4998] dpm_resume+0x110/0x2b8 >>> [ 438.409561] [7: binder:436_2: 4998] dpm_resume_end+0x1c/0x38 >>> [ 438.409570] [7: binder:436_2: 4998] suspend_devices_and_enter+0x828/0xab0 >>> [ 438.409582] [7: binder:436_2: 4998] pm_suspend+0x334/0x618 >>> [ 438.409592] [7: binder:436_2: 4998] state_store+0x104/0x144 >>> [ 438.409601] [7: binder:436_2: 4998] kobj_attr_store+0x30/0x48 >>> [ 438.409610] [7: binder:436_2: 4998] sysfs_kf_write+0x54/0x6c >>> [ 438.409619] [7: binder:436_2: 4998] kernfs_fop_write_iter+0x104/0x1a8 >>> [ 438.409628] [7: binder:436_2: 4998] vfs_write+0x24c/0x2f4 >>> [ 438.409640] [7: binder:436_2: 4998] ksys_write+0x78/0xe8 >>> [ 438.409652] [7: binder:436_2: 4998] __arm64_sys_write+0x1c/0x2c >>> [ 438.409664] [7: binder:436_2: 4998] invoke_syscall+0x58/0x114 >>> [ 438.409676] [7: binder:436_2: 4998] el0_svc_common+0xac/0xe0 >>> [ 438.409687] [7: binder:436_2: 4998] do_el0_svc+0x1c/0x28 >>> [ 438.409698] [7: binder:436_2: 4998] el0_svc+0x38/0x68 >>> [ 438.409705] [7: binder:436_2: 4998] el0t_64_sync_handler+0x68/0xbc >>> [ 438.409712] [7: binder:436_2: 4998] el0t_64_sync+0x1a8/0x1ac >>> Signed-off-by: ping.gao <ping.gao@samsung.com> >>> --- >>> drivers/mmc/host/dw_mmc.c | 12 +++++++++--- >>> 1 file changed, 9 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c >>> index c5db92bbb094..61f6986f15ef 100644 >>> --- a/drivers/mmc/host/dw_mmc.c >>> +++ b/drivers/mmc/host/dw_mmc.c >>> @@ -3633,9 +3633,15 @@ int dw_mci_runtime_resume(struct device *dev) >>> if (host->slot && >>> (mmc_host_can_gpio_cd(host->slot->mmc) || >>> !mmc_card_is_removable(host->slot->mmc))) { >>> - ret = clk_prepare_enable(host->biu_clk); >>> - if (ret) >>> - return ret; >>> + if (IS_ERR(host->biu_clk)) { >>> + dev_dbg(host->dev, "biu clock not available\n"); >>> + } else { >>> + ret = clk_prepare_enable(host->biu_clk); >>> + if (ret) { >>> + dev_err(host->dev, "failed to enable biu clock\n"); >>> + goto err; >>> + } >>> + } >>> } >>> ret = clk_prepare_enable(host->ciu_clk); >> >> ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal 2026-01-04 7:38 ` Shawn Lin @ 2026-01-04 14:48 ` Sebastian Reichel 2026-01-05 0:30 ` Shawn Lin 0 siblings, 1 reply; 8+ messages in thread From: Sebastian Reichel @ 2026-01-04 14:48 UTC (permalink / raw) To: Shawn Lin; +Cc: ping.gao, jh80.chung, ulf.hansson, linux-kernel, linux-mmc [-- Attachment #1: Type: text/plain, Size: 8273 bytes --] Hi, On Sun, Jan 04, 2026 at 03:38:42PM +0800, Shawn Lin wrote: > Hi Sevastian, > > 在 2026/01/04 星期日 14:01, Sebastian Reichel 写道: > > Hi, > > > > On Sun, Jan 04, 2026 at 10:55:48AM +0800, Shawn Lin wrote: > > > 在 2026/01/04 星期日 10:38, ping.gao 写道: > > > > some vendor doesn't use biu_clk , enable it will panic > > > > log is below: > > > > > > I still don't understand the real issue you tried to solve. > > > > > > host->biu_clk is got via devm_clk_get() in dw_mci_probe(). If > > > succeed, immediately it's enabled a few lines below. Otherwise, > > > dw_mci_probe() returns with failure. Seems you are not enabling it in > > > runtime callbacks, but why clk_prepare_enable(host->biu_clk) is able > > > to work when driver probed? > > > > Based on the error and this patch, I believe what happens is: > > > > 1. dw_mci_probe() calls devm_clk_get(host->dev, "biu") > > 2. The clock does not exist on the platform from Ping Gao, so > > host->biu_clk gets an error pointer assigned > > 3. "biu clock not available" gets printed at debug level > > 4. the error is ignored, but the error pointer is still assigned to > > host->biu_clk > > 5. in the runtime PM handler clk_prepare_enable is called for > > host->biu_clk and thus for an error pointer > > > > Thanks for the details. For example, > 1. dw_mci_exynos_probe() enables runtime PM before calling > dw_mci_pltfm_register()->dw_mci_probe(). > 2. biu_clk gets an error and propagate it to dw_mci_pltfm_register(), The error propagation does not happen. This is the current code in dw_mci_probe(): host->biu_clk = devm_clk_get(host->dev, "biu"); if (IS_ERR(host->biu_clk)) { dev_dbg(host->dev, "biu clock not available\n"); ret = PTR_ERR(host->biu_clk); if (ret == -EPROBE_DEFER) return ret; /* --- no return here --- */ } else { ret = clk_prepare_enable(host->biu_clk); if (ret) { dev_err(host->dev, "failed to enable biu clock\n"); return ret; } } This code continues probing for any error code that is not -EPROBE_DEFER. My understanding is, that this has been done intensionally, since the clock does not exist on some platforms. Effectively this is an open coded devm_clk_get_optional with the difference that you may not use any clk_* operations on the error code. A minimal fix would be to assign "host->biu_clk = NULL;" at the end of the error handling code, which would open code more of the devm_clk_get_optional() behaviour. Obviously there is no point in having this open coded and the helper existed since ages, so I strongly suggest to just use that. Either devm_clk_get_optional() or even better devm_clk_get_optional_enabled(). This results in: - less code, which is easier to understand - fixing the bug at hand - proper error handling for errors that are neither -EPROBE_DEFER nor -ENOENT. - better error/debug messaging behaviour for -EPROBE_DEFER when using dev_err_probe() instead of the dev_dbg print. Greetings, -- Sebastian > 3. runtime PM is disabled in dw_mci_exynos_probe() later if seeing error. > > Does that mean runtime PM handler is called between step 2 and step 3? > If that is the case, how could we allow this happen because the the > controller's configuaration isn't been finished yet. Or maybe I > misunderstand your point? > > > > Instead of hacking this up even further (as this patch does), > > the proper fix is to cleanup the probe function. I believe > > the complete biu clock handling in it could be reduced to this: > > > > host->biu_clk = devm_clk_get_optional_enabled(host->dev, "biu"); > > ret = PTR_ERR_OR_ZERO(host->biu_clk); > > if (ret) > > return dev_err_probe(host->dev, ret, "failed to get biu clock\n"); > > > > That will assign NULL to host->biu_clk when there is no clock > > defined and it is fine to run clk_prepare_enable() with NULL > > as clock pointer. Note, that this will handle the clock enabling > > as part of devm, so you will also have to drop the > > clk_disable_unprepare() calls from the err_clk_biu goto label > > and the extra call from dw_mci_remove(). > > > > Something similar should probably be done for host->ciu_clk, which > > seems to have the same incorrect logic. > > > > Greetings, > > > > -- Sebastian > > > > > > [ 438.400868] [7: binder:436_2: 4998] Unable to handle kernel paging request at virtual address fffffffffffffffe > > > > [ 438.400877] [7: binder:436_2: 4998] Mem abort info: > > > > [ 438.400881] [7: binder:436_2: 4998] ESR = 0x0000000096000005 > > > > [ 438.400887] [7: binder:436_2: 4998] EC = 0x25: DABT (current EL), IL = 32 bits > > > > [ 438.400894] [7: binder:436_2: 4998] SET = 0, FnV = 0 > > > > [ 438.400899] [7: binder:436_2: 4998] EA = 0, S1PTW = 0 > > > > [ 438.400904] [7: binder:436_2: 4998] FSC = 0x05: level 1 translation fault > > > > ... > > > > [ 438.409424] [7: binder:436_2: 4998] Call trace: > > > > [ 438.409429] [7: binder:436_2: 4998] clk_prepare+0x10/0x24 > > > > [ 438.409439] [7: binder:436_2: 4998] dw_mci_runtime_resume+0x50/0x2d8 [dw_mmc_samsung cd210e210975263404c28fc89778f369f8398f0c] > > > > [ 438.409471] [7: binder:436_2: 4998] dw_mci_exynos_runtime_resume+0x18/0x58 [dw_mmc_exynos_samsung 2735a594c7c9c9e8c65b0b87523fbf70dcaabfff] > > > > [ 438.409496] [7: binder:436_2: 4998] pm_generic_runtime_resume+0x40/0x58 > > > > [ 438.409506] [7: binder:436_2: 4998] pm_runtime_force_resume+0x9c/0x134 > > > > [ 438.409517] [7: binder:436_2: 4998] platform_pm_resume+0x40/0x8c > > > > [ 438.409529] [7: binder:436_2: 4998] dpm_run_callback+0x64/0x230 > > > > [ 438.409540] [7: binder:436_2: 4998] __device_resume+0x1d8/0x394 > > > > [ 438.409551] [7: binder:436_2: 4998] dpm_resume+0x110/0x2b8 > > > > [ 438.409561] [7: binder:436_2: 4998] dpm_resume_end+0x1c/0x38 > > > > [ 438.409570] [7: binder:436_2: 4998] suspend_devices_and_enter+0x828/0xab0 > > > > [ 438.409582] [7: binder:436_2: 4998] pm_suspend+0x334/0x618 > > > > [ 438.409592] [7: binder:436_2: 4998] state_store+0x104/0x144 > > > > [ 438.409601] [7: binder:436_2: 4998] kobj_attr_store+0x30/0x48 > > > > [ 438.409610] [7: binder:436_2: 4998] sysfs_kf_write+0x54/0x6c > > > > [ 438.409619] [7: binder:436_2: 4998] kernfs_fop_write_iter+0x104/0x1a8 > > > > [ 438.409628] [7: binder:436_2: 4998] vfs_write+0x24c/0x2f4 > > > > [ 438.409640] [7: binder:436_2: 4998] ksys_write+0x78/0xe8 > > > > [ 438.409652] [7: binder:436_2: 4998] __arm64_sys_write+0x1c/0x2c > > > > [ 438.409664] [7: binder:436_2: 4998] invoke_syscall+0x58/0x114 > > > > [ 438.409676] [7: binder:436_2: 4998] el0_svc_common+0xac/0xe0 > > > > [ 438.409687] [7: binder:436_2: 4998] do_el0_svc+0x1c/0x28 > > > > [ 438.409698] [7: binder:436_2: 4998] el0_svc+0x38/0x68 > > > > [ 438.409705] [7: binder:436_2: 4998] el0t_64_sync_handler+0x68/0xbc > > > > [ 438.409712] [7: binder:436_2: 4998] el0t_64_sync+0x1a8/0x1ac > > > > Signed-off-by: ping.gao <ping.gao@samsung.com> > > > > --- > > > > drivers/mmc/host/dw_mmc.c | 12 +++++++++--- > > > > 1 file changed, 9 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > > > > index c5db92bbb094..61f6986f15ef 100644 > > > > --- a/drivers/mmc/host/dw_mmc.c > > > > +++ b/drivers/mmc/host/dw_mmc.c > > > > @@ -3633,9 +3633,15 @@ int dw_mci_runtime_resume(struct device *dev) > > > > if (host->slot && > > > > (mmc_host_can_gpio_cd(host->slot->mmc) || > > > > !mmc_card_is_removable(host->slot->mmc))) { > > > > - ret = clk_prepare_enable(host->biu_clk); > > > > - if (ret) > > > > - return ret; > > > > + if (IS_ERR(host->biu_clk)) { > > > > + dev_dbg(host->dev, "biu clock not available\n"); > > > > + } else { > > > > + ret = clk_prepare_enable(host->biu_clk); > > > > + if (ret) { > > > > + dev_err(host->dev, "failed to enable biu clock\n"); > > > > + goto err; > > > > + } > > > > + } > > > > } > > > > ret = clk_prepare_enable(host->ciu_clk); > > > > > > > [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal 2026-01-04 14:48 ` Sebastian Reichel @ 2026-01-05 0:30 ` Shawn Lin 0 siblings, 0 replies; 8+ messages in thread From: Shawn Lin @ 2026-01-05 0:30 UTC (permalink / raw) To: Sebastian Reichel Cc: shawn.lin, ping.gao, jh80.chung, ulf.hansson, linux-kernel, linux-mmc 在 2026/01/04 星期日 22:48, Sebastian Reichel 写道: > Hi, > > On Sun, Jan 04, 2026 at 03:38:42PM +0800, Shawn Lin wrote: >> Hi Sevastian, >> >> 在 2026/01/04 星期日 14:01, Sebastian Reichel 写道: >>> Hi, >>> >>> On Sun, Jan 04, 2026 at 10:55:48AM +0800, Shawn Lin wrote: >>>> 在 2026/01/04 星期日 10:38, ping.gao 写道: >>>>> some vendor doesn't use biu_clk , enable it will panic >>>>> log is below: >>>> >>>> I still don't understand the real issue you tried to solve. >>>> >>>> host->biu_clk is got via devm_clk_get() in dw_mci_probe(). If >>>> succeed, immediately it's enabled a few lines below. Otherwise, >>>> dw_mci_probe() returns with failure. Seems you are not enabling it in >>>> runtime callbacks, but why clk_prepare_enable(host->biu_clk) is able >>>> to work when driver probed? >>> >>> Based on the error and this patch, I believe what happens is: >>> >>> 1. dw_mci_probe() calls devm_clk_get(host->dev, "biu") >>> 2. The clock does not exist on the platform from Ping Gao, so >>> host->biu_clk gets an error pointer assigned >>> 3. "biu clock not available" gets printed at debug level >>> 4. the error is ignored, but the error pointer is still assigned to >>> host->biu_clk >>> 5. in the runtime PM handler clk_prepare_enable is called for >>> host->biu_clk and thus for an error pointer >>> >> >> Thanks for the details. For example, >> 1. dw_mci_exynos_probe() enables runtime PM before calling >> dw_mci_pltfm_register()->dw_mci_probe(). >> 2. biu_clk gets an error and propagate it to dw_mci_pltfm_register(), > > The error propagation does not happen. This is the current code in > dw_mci_probe(): > > host->biu_clk = devm_clk_get(host->dev, "biu"); > if (IS_ERR(host->biu_clk)) { > dev_dbg(host->dev, "biu clock not available\n"); > ret = PTR_ERR(host->biu_clk); > if (ret == -EPROBE_DEFER) > return ret; > /* --- no return here --- */ > } else { > ret = clk_prepare_enable(host->biu_clk); > if (ret) { > dev_err(host->dev, "failed to enable biu clock\n"); > return ret; > } > } > > This code continues probing for any error code that is not > -EPROBE_DEFER. My understanding is, that this has been done > intensionally, since the clock does not exist on some platforms. > I never thought of biu_clk isn't been provided as it's for accessing register/fifo/interrupt/DMA requested by dwc databook. I was suprised it's the optional case for some platforms. What I was thinking is all based on that defer case. > Effectively this is an open coded devm_clk_get_optional with > the difference that you may not use any clk_* operations on the > error code. A minimal fix would be to assign "host->biu_clk = NULL;" > at the end of the error handling code, which would open code > more of the devm_clk_get_optional() behaviour. Yes, if it's optional case for some platforms, we should use devm_clk_get_optional() instead, both for biu_clk and ciu_clk. Although I will also be surprised to see ciu_clk is also optional, the code should be consistent. > > Obviously there is no point in having this open coded and the > helper existed since ages, so I strongly suggest to just use > that. Either devm_clk_get_optional() or even better > devm_clk_get_optional_enabled(). This results in: > > - less code, which is easier to understand > - fixing the bug at hand > - proper error handling for errors that are neither -EPROBE_DEFER > nor -ENOENT. > - better error/debug messaging behaviour for -EPROBE_DEFER when > using dev_err_probe() instead of the dev_dbg print. > > Greetings, > > -- Sebastian > >> 3. runtime PM is disabled in dw_mci_exynos_probe() later if seeing error. >> >> Does that mean runtime PM handler is called between step 2 and step 3? >> If that is the case, how could we allow this happen because the the >> controller's configuaration isn't been finished yet. Or maybe I >> misunderstand your point? >> >> >>> Instead of hacking this up even further (as this patch does), >>> the proper fix is to cleanup the probe function. I believe >>> the complete biu clock handling in it could be reduced to this: >>> >>> host->biu_clk = devm_clk_get_optional_enabled(host->dev, "biu"); >>> ret = PTR_ERR_OR_ZERO(host->biu_clk); >>> if (ret) >>> return dev_err_probe(host->dev, ret, "failed to get biu clock\n"); >>> >>> That will assign NULL to host->biu_clk when there is no clock >>> defined and it is fine to run clk_prepare_enable() with NULL >>> as clock pointer. Note, that this will handle the clock enabling >>> as part of devm, so you will also have to drop the >>> clk_disable_unprepare() calls from the err_clk_biu goto label >>> and the extra call from dw_mci_remove(). >>> >>> Something similar should probably be done for host->ciu_clk, which >>> seems to have the same incorrect logic. >>> >>> Greetings, >>> >>> -- Sebastian >>> >>>>> [ 438.400868] [7: binder:436_2: 4998] Unable to handle kernel paging request at virtual address fffffffffffffffe >>>>> [ 438.400877] [7: binder:436_2: 4998] Mem abort info: >>>>> [ 438.400881] [7: binder:436_2: 4998] ESR = 0x0000000096000005 >>>>> [ 438.400887] [7: binder:436_2: 4998] EC = 0x25: DABT (current EL), IL = 32 bits >>>>> [ 438.400894] [7: binder:436_2: 4998] SET = 0, FnV = 0 >>>>> [ 438.400899] [7: binder:436_2: 4998] EA = 0, S1PTW = 0 >>>>> [ 438.400904] [7: binder:436_2: 4998] FSC = 0x05: level 1 translation fault >>>>> ... >>>>> [ 438.409424] [7: binder:436_2: 4998] Call trace: >>>>> [ 438.409429] [7: binder:436_2: 4998] clk_prepare+0x10/0x24 >>>>> [ 438.409439] [7: binder:436_2: 4998] dw_mci_runtime_resume+0x50/0x2d8 [dw_mmc_samsung cd210e210975263404c28fc89778f369f8398f0c] >>>>> [ 438.409471] [7: binder:436_2: 4998] dw_mci_exynos_runtime_resume+0x18/0x58 [dw_mmc_exynos_samsung 2735a594c7c9c9e8c65b0b87523fbf70dcaabfff] >>>>> [ 438.409496] [7: binder:436_2: 4998] pm_generic_runtime_resume+0x40/0x58 >>>>> [ 438.409506] [7: binder:436_2: 4998] pm_runtime_force_resume+0x9c/0x134 >>>>> [ 438.409517] [7: binder:436_2: 4998] platform_pm_resume+0x40/0x8c >>>>> [ 438.409529] [7: binder:436_2: 4998] dpm_run_callback+0x64/0x230 >>>>> [ 438.409540] [7: binder:436_2: 4998] __device_resume+0x1d8/0x394 >>>>> [ 438.409551] [7: binder:436_2: 4998] dpm_resume+0x110/0x2b8 >>>>> [ 438.409561] [7: binder:436_2: 4998] dpm_resume_end+0x1c/0x38 >>>>> [ 438.409570] [7: binder:436_2: 4998] suspend_devices_and_enter+0x828/0xab0 >>>>> [ 438.409582] [7: binder:436_2: 4998] pm_suspend+0x334/0x618 >>>>> [ 438.409592] [7: binder:436_2: 4998] state_store+0x104/0x144 >>>>> [ 438.409601] [7: binder:436_2: 4998] kobj_attr_store+0x30/0x48 >>>>> [ 438.409610] [7: binder:436_2: 4998] sysfs_kf_write+0x54/0x6c >>>>> [ 438.409619] [7: binder:436_2: 4998] kernfs_fop_write_iter+0x104/0x1a8 >>>>> [ 438.409628] [7: binder:436_2: 4998] vfs_write+0x24c/0x2f4 >>>>> [ 438.409640] [7: binder:436_2: 4998] ksys_write+0x78/0xe8 >>>>> [ 438.409652] [7: binder:436_2: 4998] __arm64_sys_write+0x1c/0x2c >>>>> [ 438.409664] [7: binder:436_2: 4998] invoke_syscall+0x58/0x114 >>>>> [ 438.409676] [7: binder:436_2: 4998] el0_svc_common+0xac/0xe0 >>>>> [ 438.409687] [7: binder:436_2: 4998] do_el0_svc+0x1c/0x28 >>>>> [ 438.409698] [7: binder:436_2: 4998] el0_svc+0x38/0x68 >>>>> [ 438.409705] [7: binder:436_2: 4998] el0t_64_sync_handler+0x68/0xbc >>>>> [ 438.409712] [7: binder:436_2: 4998] el0t_64_sync+0x1a8/0x1ac >>>>> Signed-off-by: ping.gao <ping.gao@samsung.com> >>>>> --- >>>>> drivers/mmc/host/dw_mmc.c | 12 +++++++++--- >>>>> 1 file changed, 9 insertions(+), 3 deletions(-) >>>>> >>>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c >>>>> index c5db92bbb094..61f6986f15ef 100644 >>>>> --- a/drivers/mmc/host/dw_mmc.c >>>>> +++ b/drivers/mmc/host/dw_mmc.c >>>>> @@ -3633,9 +3633,15 @@ int dw_mci_runtime_resume(struct device *dev) >>>>> if (host->slot && >>>>> (mmc_host_can_gpio_cd(host->slot->mmc) || >>>>> !mmc_card_is_removable(host->slot->mmc))) { >>>>> - ret = clk_prepare_enable(host->biu_clk); >>>>> - if (ret) >>>>> - return ret; >>>>> + if (IS_ERR(host->biu_clk)) { >>>>> + dev_dbg(host->dev, "biu clock not available\n"); >>>>> + } else { >>>>> + ret = clk_prepare_enable(host->biu_clk); >>>>> + if (ret) { >>>>> + dev_err(host->dev, "failed to enable biu clock\n"); >>>>> + goto err; >>>>> + } >>>>> + } >>>>> } >>>>> ret = clk_prepare_enable(host->ciu_clk); >>>> >>>> >> ^ permalink raw reply [flat|nested] 8+ messages in thread
[parent not found: <CGME20251223044225epcas5p2b5afed35eec4ba996a5a223e4b8779c9@epcas5p2.samsung.com>]
* [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal [not found] <CGME20251223044225epcas5p2b5afed35eec4ba996a5a223e4b8779c9@epcas5p2.samsung.com> @ 2025-12-23 4:46 ` ping.gao 2025-12-30 15:17 ` Ulf Hansson 0 siblings, 1 reply; 8+ messages in thread From: ping.gao @ 2025-12-23 4:46 UTC (permalink / raw) To: jh80.chung, ulf.hansson, linux-mmc, linux-kernel; +Cc: ping.gao exynos doesn't use biu_clk , enable it will panic Signed-off-by: ping.gao <ping.gao@samsung.com> --- drivers/mmc/host/dw_mmc.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index c5db92bbb094..61f6986f15ef 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -3633,9 +3633,15 @@ int dw_mci_runtime_resume(struct device *dev) if (host->slot && (mmc_host_can_gpio_cd(host->slot->mmc) || !mmc_card_is_removable(host->slot->mmc))) { - ret = clk_prepare_enable(host->biu_clk); - if (ret) - return ret; + if (IS_ERR(host->biu_clk)) { + dev_dbg(host->dev, "biu clock not available\n"); + } else { + ret = clk_prepare_enable(host->biu_clk); + if (ret) { + dev_err(host->dev, "failed to enable biu clock\n"); + goto err; + } + } } ret = clk_prepare_enable(host->ciu_clk); -- 2.50.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal 2025-12-23 4:46 ` ping.gao @ 2025-12-30 15:17 ` Ulf Hansson 0 siblings, 0 replies; 8+ messages in thread From: Ulf Hansson @ 2025-12-30 15:17 UTC (permalink / raw) To: ping.gao; +Cc: jh80.chung, linux-mmc, linux-kernel On Tue, 23 Dec 2025 at 05:42, ping.gao <ping.gao@samsung.com> wrote: > > exynos doesn't use biu_clk , enable it will panic Please elaborate a bit more on what the patch does. > > Signed-off-by: ping.gao <ping.gao@samsung.com> > --- > drivers/mmc/host/dw_mmc.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index c5db92bbb094..61f6986f15ef 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -3633,9 +3633,15 @@ int dw_mci_runtime_resume(struct device *dev) > if (host->slot && > (mmc_host_can_gpio_cd(host->slot->mmc) || > !mmc_card_is_removable(host->slot->mmc))) { > - ret = clk_prepare_enable(host->biu_clk); > - if (ret) > - return ret; > + if (IS_ERR(host->biu_clk)) { > + dev_dbg(host->dev, "biu clock not available\n"); > + } else { > + ret = clk_prepare_enable(host->biu_clk); > + if (ret) { > + dev_err(host->dev, "failed to enable biu clock\n"); > + goto err; > + } > + } Rather than making the change in dw_mci_runtime_resume(), I suggest we set "host->biu_clk = NULL" in dw_mci_probe(), rather than keeping its error code. In this way, clk_prepare_enable() will not return an error code above. > } > > ret = clk_prepare_enable(host->ciu_clk); > -- > 2.50.1 > Kind regards Uffe ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2026-01-05 1:46 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
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[not found] <CGME20260104023451epcas5p391708610b5ce46d0e2a5f4bfbad01c71@epcas5p3.samsung.com>
2026-01-04 2:38 ` [PATCH] MMC:dw_mmc:when enable biu_clk should check whether this clk is normal ping.gao
2026-01-04 2:55 ` Shawn Lin
2026-01-04 6:01 ` Sebastian Reichel
2026-01-04 7:38 ` Shawn Lin
2026-01-04 14:48 ` Sebastian Reichel
2026-01-05 0:30 ` Shawn Lin
[not found] <CGME20251223044225epcas5p2b5afed35eec4ba996a5a223e4b8779c9@epcas5p2.samsung.com>
2025-12-23 4:46 ` ping.gao
2025-12-30 15:17 ` Ulf Hansson
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