lkml.org 
[lkml]   [2022]   [Feb]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH V0 1/1] ALSA: pcm: fix blocking while loop in snd_pcm_update_hw_ptr0()
On Fri, 25 Feb 2022 13:26:36 +0100,
Raghu Ballappa Bankapur wrote:
>
> Hi Takashi,
>
> Thanks for your feedback.
>
> I see your below statement
>
> But, having either this zero check or minimal hw_ptr_buffer_jiffies=1
> would be good in anyway, even if we add more check for the hw_params
> for no-period-wakeup case.
>
> Please review if those changes are Ok

If you mean about your posted patch for "those changes", as Jaroslav
suggested in the thread, we may take a different approach: just set
the minimal hw_ptr_buffer_jiffies to 1.

Could you try this and submit the fix if that works for you?


thanks,

Takashi

>
> Regards
> Raghu
>
> On 2/25/2022 4:53 PM, Takashi Iwai wrote:
>
> On Fri, 25 Feb 2022 11:52:05 +0100,
> Jaroslav Kysela wrote:
>
> On 25. 02. 22 11:39, Raghu Bankapur wrote:
>
> When period interrupts are disabled, while loop in snd_pcm_update_hw_ptr0()
> results in the machine locking up if runtime->hw_ptr_buffer_jiffies is 0.
> Validate runtime->hw_ptr_buffer_jiffies value before while loop to avoid
> delta check.
>
> I would set hw_ptr_buffer_jiffies to 1 in this case in snd_pcm_post_start().
>
> I thought of it at the first glance, but after reading the code again,
> I doubt whether it makes sense at all to allow this condition.
> Since the buffer size is too small and the rate is too high, we can't
> calculate the buffer crossing condition accurately under such
> condition.
>
> But, having either this zero check or minimal hw_ptr_buffer_jiffies=1
> would be good in anyway, even if we add more check for the hw_params
> for no-period-wakeup case.
>
> thanks,
>
> Takashi
>
>

\
 
 \ /
  Last update: 2022-02-28 16:59    [W:0.036 / U:0.784 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site