[PATCH] ALSA: document that struct __snd_pcm_mmap_control64 is messed up
I suppose this can't be changed anymore due to binary compat concerns.
Signed-off-by: Oswald Buddenhagen oswald.buddenhagen@gmx.de --- include/uapi/sound/asound.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index de6810e94abe..595a683968bc 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -570,7 +570,7 @@ struct __snd_pcm_mmap_status64 { struct __snd_pcm_mmap_control64 { __pad_before_uframe __pad1; snd_pcm_uframes_t appl_ptr; /* RW: appl ptr (0...boundary-1) */ - __pad_before_uframe __pad2; + __pad_before_uframe __pad2; // BUG: this should have been __pad_after_uframe!
__pad_before_uframe __pad3; snd_pcm_uframes_t avail_min; /* RW: min available frames for wakeup */
On Wed, 05 Apr 2023 22:12:19 +0200, Oswald Buddenhagen wrote:
I suppose this can't be changed anymore due to binary compat concerns.
Yes, please check the thread at https://lore.kernel.org/all/29QBMJU8DE71E.2YZSH8IHT5HMH@mforney.org/
Signed-off-by: Oswald Buddenhagen oswald.buddenhagen@gmx.de
include/uapi/sound/asound.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index de6810e94abe..595a683968bc 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -570,7 +570,7 @@ struct __snd_pcm_mmap_status64 { struct __snd_pcm_mmap_control64 { __pad_before_uframe __pad1; snd_pcm_uframes_t appl_ptr; /* RW: appl ptr (0...boundary-1) */
- __pad_before_uframe __pad2;
- __pad_before_uframe __pad2; // BUG: this should have been __pad_after_uframe!
Writing this alone doesn't help much. Actual help would be to mention that this typo is kept intentionally.
Takashi
On Thu, Apr 06, 2023 at 08:03:39AM +0200, Takashi Iwai wrote:
On Wed, 05 Apr 2023 22:12:19 +0200, Oswald Buddenhagen wrote:
I suppose this can't be changed anymore due to binary compat concerns.
Yes, please check the thread at https://lore.kernel.org/all/29QBMJU8DE71E.2YZSH8IHT5HMH@mforney.org/
- __pad_before_uframe __pad2; // BUG: this should have been __pad_after_uframe!
Writing this alone doesn't help much. Actual help would be to mention that this typo is kept intentionally.
hmm, my thinking is that the immediate response to reading that comment would be "so why don't you change it?!", at which point the person would either realize by themselves that this is subject to binary compat constraints, or would git-blame it and see the explanation.
anyway, my concern is keeping this *short*, so it doesn't distract.
maybe
// BUG: should be __pad_after_uframe, but binary compat
would do, though obviously the grammar kinda sucks.
the (too) long version could be
// BUG: this should be __pad_after_uframe, but // binary compatibility constraints prevent a fix.
choose your death, i'll deliver it. ;-)
On Thu, 06 Apr 2023 08:46:51 +0200, Oswald Buddenhagen wrote:
On Thu, Apr 06, 2023 at 08:03:39AM +0200, Takashi Iwai wrote:
On Wed, 05 Apr 2023 22:12:19 +0200, Oswald Buddenhagen wrote:
I suppose this can't be changed anymore due to binary compat concerns.
Yes, please check the thread at https://lore.kernel.org/all/29QBMJU8DE71E.2YZSH8IHT5HMH@mforney.org/
- __pad_before_uframe __pad2; // BUG: this should have been __pad_after_uframe!
Writing this alone doesn't help much. Actual help would be to mention that this typo is kept intentionally.
hmm, my thinking is that the immediate response to reading that comment would be "so why don't you change it?!", at which point the person would either realize by themselves that this is subject to binary compat constraints, or would git-blame it and see the explanation.
anyway, my concern is keeping this *short*, so it doesn't distract.
maybe
// BUG: should be __pad_after_uframe, but binary compat
would do, though obviously the grammar kinda sucks.
the (too) long version could be
// BUG: this should be __pad_after_uframe, but // binary compatibility constraints prevent a fix.
choose your death, i'll deliver it. ;-)
The "BUG:" suffix should be dropped. This would catch eyes of (badly) trained kernel programmers as if it were a kernel panic message :)
Also the term "binary compatibility" is ambiguous in this context -- especially because we're dealing with the code that treats the 32/64bit binary compatibility.
But, yeah, I'm for that direction.
thanks,
Takashi
On Thu, Apr 06, 2023 at 09:48:40AM +0200, Takashi Iwai wrote:
The "BUG:" suffix should be dropped. This would catch eyes of (badly) trained kernel programmers as if it were a kernel panic message :)
done
Also the term "binary compatibility" is ambiguous in this context -- especially because we're dealing with the code that treats the 32/64bit binary compatibility.
i wasn't sure what to make of that. how about this:
-- >8 --
I'm not the first one to run into this, see e.g. https://lore.kernel.org/all/29QBMJU8DE71E.2YZSH8IHT5HMH@mforney.org/
Signed-off-by: Oswald Buddenhagen oswald.buddenhagen@gmx.de --- include/uapi/sound/asound.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index de6810e94abe..7eecc99ddef7 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -570,7 +570,8 @@ struct __snd_pcm_mmap_status64 { struct __snd_pcm_mmap_control64 { __pad_before_uframe __pad1; snd_pcm_uframes_t appl_ptr; /* RW: appl ptr (0...boundary-1) */ - __pad_before_uframe __pad2; + __pad_before_uframe __pad2; // This should be __pad_after_uframe, but binary + // backwards compatibility constraints prevent a fix.
__pad_before_uframe __pad3; snd_pcm_uframes_t avail_min; /* RW: min available frames for wakeup */
On Thu, 06 Apr 2023 13:15:45 +0200, Oswald Buddenhagen wrote:
On Thu, Apr 06, 2023 at 09:48:40AM +0200, Takashi Iwai wrote:
The "BUG:" suffix should be dropped. This would catch eyes of (badly) trained kernel programmers as if it were a kernel panic message :)
done
Also the term "binary compatibility" is ambiguous in this context -- especially because we're dealing with the code that treats the 32/64bit binary compatibility.
i wasn't sure what to make of that. how about this:
-- >8 --
I'm not the first one to run into this, see e.g. https://lore.kernel.org/all/29QBMJU8DE71E.2YZSH8IHT5HMH@mforney.org/
Signed-off-by: Oswald Buddenhagen oswald.buddenhagen@gmx.de
include/uapi/sound/asound.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index de6810e94abe..7eecc99ddef7 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -570,7 +570,8 @@ struct __snd_pcm_mmap_status64 { struct __snd_pcm_mmap_control64 { __pad_before_uframe __pad1; snd_pcm_uframes_t appl_ptr; /* RW: appl ptr (0...boundary-1) */
- __pad_before_uframe __pad2;
- __pad_before_uframe __pad2; // This should be __pad_after_uframe, but binary
// backwards compatibility constraints prevent a fix.
Looks much better. Care to resubmit v2 patch?
Thanks!
Takashi
On Thu, Apr 06, 2023 at 02:29:44PM +0200, Takashi Iwai wrote:
Care to resubmit v2 patch?
that *was* a v2 patch - you can git-am the mail with --scissors (at least if i got it right). not acceptable?
On Thu, 06 Apr 2023 14:34:36 +0200, Oswald Buddenhagen wrote:
On Thu, Apr 06, 2023 at 02:29:44PM +0200, Takashi Iwai wrote:
Care to resubmit v2 patch?
that *was* a v2 patch - you can git-am the mail with --scissors (at least if i got it right). not acceptable?
Please resubmit properly. Nowadays commits have the link to the mail of the patch submission, and such mixup makes it harder to follow.
Takashi
participants (2)
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Oswald Buddenhagen -
Takashi Iwai