Re: [Nouveau] [PATCH] drm/nouveau/kms: Implement KDB debug hooks for nouveau KMS.

[Jason Wessel <jason.wessel@windriver.com>]

On 09/24/2010 03:50 PM, Maxim Levitsky wrote:
>   
>> [Dropped nouveau list, because this is offtopic there]
>>
>> I pretty much got to the bottom of this.
>> There are 2 separate issues:
>>
>>
>> 1. SysRq handler is now a input 'filter', which means that it can 'eat'
>> input events, so they don't show up on input bus.
>> It does so while sysrq key is down.
>> So sysrq and 'g' events never reach the kernel kbd driver and therefore
>> the hack to release them doesn't work.
>>
>> 2. The kbd_clear_keys_helper injects the keyup events alright, but it
>> doesn't inject SYN events, and therefore X evdev driver doesn't pick
>> these injected events untill next SYN event. 
>>
>> This patch makes key release work in expense of showing sysrq key to userspace, which isn't that good,
>> because now Alt+SysRQ causes a screen capture by default.
>> In my opinion the sysrq filter should stay.
>> We should just make kdb hook into atkbd and do the key release there.
>> This should both result in cleaner/more robust code, and make this issue disappear.
>> I'll look at doing that.
>>
>>
>> diff --git a/drivers/char/keyboard.c b/drivers/char/keyboard.c
>> index 0c6c641..7df6af5 100644
>> --- a/drivers/char/keyboard.c
>> +++ b/drivers/char/keyboard.c
>> @@ -368,6 +368,7 @@ static int kbd_clear_keys_helper(struct input_handle *handle, void *data)
>>  {
>>  	unsigned int *keycode = data;
>>  	input_inject_event(handle, EV_KEY, *keycode, 0);
>> +	input_inject_event(handle, EV_SYN, SYN_REPORT, 0);
>>  	return 0;
>>  }
>>  
>> diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
>> index ef31bb8..db1eb12 100644
>> --- a/drivers/char/sysrq.c
>> +++ b/drivers/char/sysrq.c
>> @@ -601,7 +601,7 @@ static bool sysrq_filter(struct input_handle *handle, unsigned int type,
>>  	}
>>  
>>  out:
>> -	return sysrq_down;
>> +	return 0;
>>  }
>>  
>>  static int sysrq_connect(struct input_handler *handler,
>>
>>
>> Best regards,
>> 	Maxim Levitsky
>>
>>     

Hi Maxim,

Is it the case that this patch takes care of masking the sysrq event
from user space?

Originally before it became an input filter I had a patch to the
keyboard.c to completely consume the keypress of the sysrq-g.

I have been less than successful at getting the keyboard changes
upstreamed, and I was probably going to ping AKPM, because on that front
I had not received any kind of response either (linux-input that is).

Certainly I can carry your patch in my branch until we can determine a
final upstream design.

Thanks,
Jason.

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