Messages in this thread Patch in this message | | | Date | Tue, 10 Jan 2023 16:39:47 +0800 | Subject | Re: [PATCH v1] i2c: i2c-core-base: Modify the maximum idr id for i2c adapter | From | Riwen Lu <> |
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在 2023/1/9 23:13, Wolfram Sang 写道: > On Fri, Dec 16, 2022 at 10:07:51AM +0800, Riwen Lu wrote: >> From: Riwen Lu <luriwen@kylinos.cn> >> >> Change the maximum idr ID to INT_MAX for i2c adapter. >> This fix the following adding i2c adapter error while the idr with >> adap->nr has been allocated by other i2c driver, and find a proper ID > > How did this happen that another i2c driver could get this? Were you > able to follow the code paths that lead to this situation? > Yes, it's happened in Phytium(Arm64) platform with MWV207 GPU.
1. The MWV207 GPU driver has registered I2C adapter, and allocated idr id 0-6 with i2c_adapter_idr.
# cd /sys/class/i2c-adapter/i2c-0/ # ls i2c-0 i2c-1 i2c-2 i2c-3 i2c-4 i2c-5 i2c-6 # cd i2c-0/ # ls delete_device device i2c-dev name new_device power subsystem uevent # cat name MWV207_I2C_0
2. The BIOS's ACPI DSDT has declared I2C device with _UID 0 as following:
Device (I2C0) { Name (_HID, "PHYT0038") // _HID: Hardware ID Name (_UID, Zero) // _UID: Unique ID Name (_CRS, ResourceTemplate () { Memory32Fixed (ReadWrite, 0x28014000, 0x00001000, ) Interrupt (ResourceConsumer, Level, ActiveHigh, Exclusive, ,, ) { 0x0000007C, } })
... }
The Phytium i2c driver would register the i2c adapter with idr id 0 by calling function i2c_add_numbered_adapter(adap). Then, function idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); allocate the idr failed because idr id adap->nr(It equal to _UID) has been allocated by MWV207 GPU, and print the following error:
couldn't get idr i2c-phytium-platform PHYT0038:00: fail to add adapter: -16
This patch can solve the problem. >> for it. >> [ 357.620685][ 3] [ T3655] ------------[ cut here ]------------ >> [ 357.626544][ 3] [ T3655] couldn't get idr >> >> Signed-off-by: Riwen Lu <luriwen@kylinos.cn> >> --- >> drivers/i2c/i2c-core-base.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c >> index 7539b0740351..c2982861057a 100644 >> --- a/drivers/i2c/i2c-core-base.c >> +++ b/drivers/i2c/i2c-core-base.c >> @@ -1535,11 +1535,12 @@ static int __i2c_add_numbered_adapter(struct i2c_adapter *adap) >> int id; >> >> mutex_lock(&core_lock); >> - id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL); >> + id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, 0, GFP_KERNEL); >> mutex_unlock(&core_lock); >> if (WARN(id < 0, "couldn't get idr")) >> return id == -ENOSPC ? -EBUSY : id; >> >> + adap->nr = id; >> return i2c_register_adapter(adap); >> } >> >> -- >> 2.25.1 >>
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