diff mbox series

usb: typec: nb7vpq904m: add CONFIG_DRM dependency

Message ID 20230622101813.3453772-1-arnd@kernel.org (mailing list archive)
State New, archived
Headers show
Series usb: typec: nb7vpq904m: add CONFIG_DRM dependency | expand

Commit Message

Arnd Bergmann June 22, 2023, 10:18 a.m. UTC
From: Arnd Bergmann <arnd@arndb.de>

This driver calls directly into DRM functions and fails to link if
that is disabled:

ld.lld: error: undefined symbol: devm_drm_bridge_add
ld.lld: error: undefined symbol: devm_drm_of_get_bridge
>>> referenced by nb7vpq904m.c
>>>               drivers/usb/typec/mux/nb7vpq904m.o:(nb7vpq904m_probe) in archive vmlinux.a

Fixes: 88d8f3ac9c67e ("usb: typec: add support for the nb7vpq904m Type-C Linear Redriver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/usb/typec/mux/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Neil Armstrong June 22, 2023, 10:39 a.m. UTC | #1
Hi,

On 22/06/2023 12:18, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> This driver calls directly into DRM functions and fails to link if
> that is disabled:
> 
> ld.lld: error: undefined symbol: devm_drm_bridge_add
> ld.lld: error: undefined symbol: devm_drm_of_get_bridge
>>>> referenced by nb7vpq904m.c
>>>>                drivers/usb/typec/mux/nb7vpq904m.o:(nb7vpq904m_probe) in archive vmlinux.a
> 
> Fixes: 88d8f3ac9c67e ("usb: typec: add support for the nb7vpq904m Type-C Linear Redriver")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   drivers/usb/typec/mux/Kconfig | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
> index 8c4d6b8fb75c3..f53ae24b6c048 100644
> --- a/drivers/usb/typec/mux/Kconfig
> +++ b/drivers/usb/typec/mux/Kconfig
> @@ -37,7 +37,7 @@ config TYPEC_MUX_INTEL_PMC
>   
>   config TYPEC_MUX_NB7VPQ904M
>   	tristate "On Semiconductor NB7VPQ904M Type-C redriver driver"
> -	depends on I2C
> +	depends on I2C && DRM
>   	select REGMAP_I2C
>   	help
>   	  Say Y or M if your system has a On Semiconductor NB7VPQ904M Type-C

I think it could be :

+	depends on DRM || DRM=n
+	select DRM_PANEL_BRIDGE if DRM

Neil
Arnd Bergmann June 22, 2023, 11:24 a.m. UTC | #2
On Thu, Jun 22, 2023, at 12:39, Neil Armstrong wrote:
> Hi,
>
> On 22/06/2023 12:18, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> This driver calls directly into DRM functions and fails to link if
>> that is disabled:
>> 
>> ld.lld: error: undefined symbol: devm_drm_bridge_add
>> ld.lld: error: undefined symbol: devm_drm_of_get_bridge
>>>>> referenced by nb7vpq904m.c
>>>>>                drivers/usb/typec/mux/nb7vpq904m.o:(nb7vpq904m_probe) in archive vmlinux.a
>> 
>> Fixes: 88d8f3ac9c67e ("usb: typec: add support for the nb7vpq904m Type-C Linear Redriver")
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> ---
>>   drivers/usb/typec/mux/Kconfig | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
>> index 8c4d6b8fb75c3..f53ae24b6c048 100644
>> --- a/drivers/usb/typec/mux/Kconfig
>> +++ b/drivers/usb/typec/mux/Kconfig
>> @@ -37,7 +37,7 @@ config TYPEC_MUX_INTEL_PMC
>>   
>>   config TYPEC_MUX_NB7VPQ904M
>>   	tristate "On Semiconductor NB7VPQ904M Type-C redriver driver"
>> -	depends on I2C
>> +	depends on I2C && DRM
>>   	select REGMAP_I2C
>>   	help
>>   	  Say Y or M if your system has a On Semiconductor NB7VPQ904M Type-C
>
> I think it could be :
>
> +	depends on DRM || DRM=n
> +	select DRM_PANEL_BRIDGE if DRM

As far as I can tell, this would only avoid the link error
against devm_drm_of_get_bridge(), but not the one against
devm_drm_bridge_add(), which is defined in drm.ko through
drivers/gpu/drm/drm_bridge.c.

    Arnd
Neil Armstrong June 22, 2023, 3:39 p.m. UTC | #3
Hi,

On 22/06/2023 13:24, Arnd Bergmann wrote:
> On Thu, Jun 22, 2023, at 12:39, Neil Armstrong wrote:
>> Hi,
>>
>> On 22/06/2023 12:18, Arnd Bergmann wrote:
>>> From: Arnd Bergmann <arnd@arndb.de>
>>>
>>> This driver calls directly into DRM functions and fails to link if
>>> that is disabled:
>>>
>>> ld.lld: error: undefined symbol: devm_drm_bridge_add
>>> ld.lld: error: undefined symbol: devm_drm_of_get_bridge
>>>>>> referenced by nb7vpq904m.c
>>>>>>                 drivers/usb/typec/mux/nb7vpq904m.o:(nb7vpq904m_probe) in archive vmlinux.a
>>>
>>> Fixes: 88d8f3ac9c67e ("usb: typec: add support for the nb7vpq904m Type-C Linear Redriver")
>>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>>> ---
>>>    drivers/usb/typec/mux/Kconfig | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
>>> index 8c4d6b8fb75c3..f53ae24b6c048 100644
>>> --- a/drivers/usb/typec/mux/Kconfig
>>> +++ b/drivers/usb/typec/mux/Kconfig
>>> @@ -37,7 +37,7 @@ config TYPEC_MUX_INTEL_PMC
>>>    
>>>    config TYPEC_MUX_NB7VPQ904M
>>>    	tristate "On Semiconductor NB7VPQ904M Type-C redriver driver"
>>> -	depends on I2C
>>> +	depends on I2C && DRM
>>>    	select REGMAP_I2C
>>>    	help
>>>    	  Say Y or M if your system has a On Semiconductor NB7VPQ904M Type-C
>>
>> I think it could be :
>>
>> +	depends on DRM || DRM=n
>> +	select DRM_PANEL_BRIDGE if DRM
> 
> As far as I can tell, this would only avoid the link error
> against devm_drm_of_get_bridge(), but not the one against
> devm_drm_bridge_add(), which is defined in drm.ko through
> drivers/gpu/drm/drm_bridge.c.

I'm trying to reproduce such situation, but so fail I fail.

In the driver there's a guard to avoid calling into DRM functions
when disabled:
#if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_DRM_PANEL_BRIDGE)

so I wonder which kind on config leaded to that since
CONFIG_DRM_PANEL_BRIDGE is only enabled when DRM_PANEL and DRM are.

Neil

> 
>      Arnd
Arnd Bergmann June 22, 2023, 3:57 p.m. UTC | #4
On Thu, Jun 22, 2023, at 17:39, Neil Armstrong wrote:
> On 22/06/2023 13:24, Arnd Bergmann wrote:
>> On Thu, Jun 22, 2023, at 12:39, Neil Armstrong wrote:
>>>>    
>>>>    config TYPEC_MUX_NB7VPQ904M
>>>>    	tristate "On Semiconductor NB7VPQ904M Type-C redriver driver"
>>>> -	depends on I2C
>>>> +	depends on I2C && DRM
>>>>    	select REGMAP_I2C
>>>>    	help
>>>>    	  Say Y or M if your system has a On Semiconductor NB7VPQ904M Type-C
>>>
>>> I think it could be :
>>>
>>> +	depends on DRM || DRM=n
>>> +	select DRM_PANEL_BRIDGE if DRM
>> 
>> As far as I can tell, this would only avoid the link error
>> against devm_drm_of_get_bridge(), but not the one against
>> devm_drm_bridge_add(), which is defined in drm.ko through
>> drivers/gpu/drm/drm_bridge.c.
>
> I'm trying to reproduce such situation, but so fail I fail.
>
> In the driver there's a guard to avoid calling into DRM functions
> when disabled:
> #if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_DRM_PANEL_BRIDGE)

Ah, you are right. I got confused because the check is in
header file for devm_drm_of_get_bridge(), but not for
devm_drm_bridge_add(), which has the check in the source
file as you point out.

> so I wonder which kind on config leaded to that since
> CONFIG_DRM_PANEL_BRIDGE is only enabled when DRM_PANEL and DRM are.

I only saw the original issue with

CONFIG_DRM=m
CONFIG_DRM_PANEL=y
CONFIG_DRM_BRIDGE=y
CONFIG_DRM_PANEL_BRIDGE=y
CONFIG_TYPEC_MUX_NB7VPQ904M=y

and since CONFIG_DRM_PANEL_BRIDGE already depends on CONFIG_DRM,
I think that is the only one that can go wrong, so your
suggestion of

   depends on DRM || DRM=n

should be sufficient. I see that DRM_PANEL, DRM_BRIDGE and
DRM_PANEL_BRIDGE are now always =y whenever DRM is enabled,
so I don't think the 'select CONFIG_DRM_PANEL_BRIDGE' serves
any purpose any more, but it's also harmless if you think it
helps for clarification.

Can you send the updated patch, or should I?


     Arnd
Neil Armstrong June 22, 2023, 4:05 p.m. UTC | #5
On 22/06/2023 17:57, Arnd Bergmann wrote:
> On Thu, Jun 22, 2023, at 17:39, Neil Armstrong wrote:
>> On 22/06/2023 13:24, Arnd Bergmann wrote:
>>> On Thu, Jun 22, 2023, at 12:39, Neil Armstrong wrote:
>>>>>     
>>>>>     config TYPEC_MUX_NB7VPQ904M
>>>>>     	tristate "On Semiconductor NB7VPQ904M Type-C redriver driver"
>>>>> -	depends on I2C
>>>>> +	depends on I2C && DRM
>>>>>     	select REGMAP_I2C
>>>>>     	help
>>>>>     	  Say Y or M if your system has a On Semiconductor NB7VPQ904M Type-C
>>>>
>>>> I think it could be :
>>>>
>>>> +	depends on DRM || DRM=n
>>>> +	select DRM_PANEL_BRIDGE if DRM
>>>
>>> As far as I can tell, this would only avoid the link error
>>> against devm_drm_of_get_bridge(), but not the one against
>>> devm_drm_bridge_add(), which is defined in drm.ko through
>>> drivers/gpu/drm/drm_bridge.c.
>>
>> I'm trying to reproduce such situation, but so fail I fail.
>>
>> In the driver there's a guard to avoid calling into DRM functions
>> when disabled:
>> #if IS_ENABLED(CONFIG_OF) && IS_ENABLED(CONFIG_DRM_PANEL_BRIDGE)
> 
> Ah, you are right. I got confused because the check is in
> header file for devm_drm_of_get_bridge(), but not for
> devm_drm_bridge_add(), which has the check in the source
> file as you point out.
> 
>> so I wonder which kind on config leaded to that since
>> CONFIG_DRM_PANEL_BRIDGE is only enabled when DRM_PANEL and DRM are.
> 
> I only saw the original issue with
> 
> CONFIG_DRM=m
> CONFIG_DRM_PANEL=y
> CONFIG_DRM_BRIDGE=y
> CONFIG_DRM_PANEL_BRIDGE=y
> CONFIG_TYPEC_MUX_NB7VPQ904M=y

Ok now I see it

> 
> and since CONFIG_DRM_PANEL_BRIDGE already depends on CONFIG_DRM,
> I think that is the only one that can go wrong, so your
> suggestion of
> 
>     depends on DRM || DRM=n
> 
> should be sufficient. I see that DRM_PANEL, DRM_BRIDGE and
> DRM_PANEL_BRIDGE are now always =y whenever DRM is enabled,
> so I don't think the 'select CONFIG_DRM_PANEL_BRIDGE' serves
> any purpose any more, but it's also harmless if you think it
> helps for clarification.

Yes DRM || DRM=n seems sufficient, but having
select DRM_PANEL_BRIDGE if DRM could clarify things.

> 
> Can you send the updated patch, or should I?

I'll send an updated patch,

Thanks,
Neil

> 
> 
>       Arnd
diff mbox series

Patch

diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
index 8c4d6b8fb75c3..f53ae24b6c048 100644
--- a/drivers/usb/typec/mux/Kconfig
+++ b/drivers/usb/typec/mux/Kconfig
@@ -37,7 +37,7 @@  config TYPEC_MUX_INTEL_PMC
 
 config TYPEC_MUX_NB7VPQ904M
 	tristate "On Semiconductor NB7VPQ904M Type-C redriver driver"
-	depends on I2C
+	depends on I2C && DRM
 	select REGMAP_I2C
 	help
 	  Say Y or M if your system has a On Semiconductor NB7VPQ904M Type-C