From mboxrd@z Thu Jan 1 00:00:00 1970 From: bugtrack@alsa-project.org Subject: [ALSA - driver 0000951]: Fix bugs with early IRQs mishandling, missing silence fill, and wrong timing calculations Date: Thu, 3 Mar 2005 15:03:19 +0100 Message-ID: <03cbaa3ba5f0f8b49c3fa26bf3cc2829@bugtrack.alsa-project.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Received: from bugtrack.alsa-project.org (gate.perex.cz [82.113.61.162]) by alsa.alsa-project.org (ALSA's E-mail Delivery System) with ESMTP id 61725194 for ; Thu, 3 Mar 2005 15:03:19 +0100 (MET) Sender: alsa-devel-admin@lists.sourceforge.net Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: alsa-devel@alsa-project.org List-Id: alsa-devel@alsa-project.org A NOTE has been added to this issue. ====================================================================== ====================================================================== Reported By: charles_levert Assigned To: ====================================================================== Project: ALSA - driver Issue ID: 951 Category: CORE - pcm Reproducibility: always Severity: major Priority: normal Status: new Distribution: Kernel Version: 2.4.22 ====================================================================== Date Submitted: 02-28-2005 21:26 CET Last Modified: 03-03-2005 15:03 CET ====================================================================== Summary: Fix bugs with early IRQs mishandling, missing silence fill, and wrong timing calculations Description: A patch is forthcoming. Here is the text from the patch preamble. This patch is against alsa-driver-1.0.8. It covers: alsa-kernel/core/pcm_lib.c alsa-kernel/include/pcm.h alsa-kernel/core/pcm_native.c alsa-kernel/core/oss/pcm_oss.c The main changes are in the first listed file. An original bug description was filed under "[ALSA - driver] PCI - cmipci": since the problems were first observed on this hardware. The patch fixes the following problems: -- Properly handle early IRQs in snd_pcm_update_hw_ptr_interrupt() in pcm_lib.c. This does occur, at least with CMI8738MC6 hardware. This bug had a major impact that caused the DMAs to run for too long and irritating noise to be heard at the end of playback. -- Properly compute estimated time of next interrupt in snd_pcm_update_hw_ptr_interrupt() in pcm_lib.c; this is no longer done with a "... % runtime->period_size" kludge (which didn't even attempt to round to nearest instead of merely truncating). -- Test whether hw_avail is big enough to handle the next runtime->period_size in snd_pcm_update_hw_ptr_post() in pcm_lib.c, otherwise call snd_pcm_tick_prepare() to tentatively set up a timer if needed (to be able to take earlier action in that case). -- Centralize all folding of values with regard to runtime->boundary in the new snd_pcm_next_buf() function in pcm_lib.c. All relevant values are now systematically in coherent synchronization without resorting to the ugly and error-prone "value %= runtime->boundary" kludge all over the place; unobvious wrapping conditions testing is no longer needed in these places. A safe zone worth one runtime->buffer_size is now kept on the left side of the operating interval, just like it was the case for the right side; this is necessary for proper simplified operation. -- Direct manipulations of values with respect to runtime->boundary needed to be brought in line with new proper practices (and thus simplified) in pcm.h, pcm_lib.c, pcm_native.c, and pcm_oss.c. -- Isolate the second part of snd_pcm_playback_silence() in the new snd_pcm_playback_silence_fill() function in pcm_lib.c. This makes the code more readable since the task this performs should not be confused with what is done in the remaining first part of snd_pcm_playback_silence(). The isolated code is unchanged. -- Rewrite the remaining first part of snd_pcm_playback_silence() to properly handle all situations, including computing minimum silence insertion even when "runtime->silence_size == 0". This is needed for proper operation of the aplay program, for one, and is much more forgiving on the user; insertion of silence samples in user space was always useless and a wrong solution anyway (but user space specification of kernel space silence insertion is useful and still very much supported). The code is now much more straightforward to read. Updates of runtime->control->appl_ptr (due to the user writing samples) and updates to runtime->status->hw_ptr (due to the audio hardware consuming samples) are now _both_ properly accounted for in all cases; the new code makes this much more obvious. -- All calls to snd_pcm_playback_silence() in pcm_lib.c and pcm_native.c must no longer be under the "runtime->silence_size > 0" condition. -- Properly perform rounded-up integer division in snd_pcm_system_tick_set() in pcm_lib.c. This only had a minor impact. -- Properly compute distance to next interrupt in snd_pcm_tick_prepare() in pcm_lib.c; again, avoid using any "... % runtime->period_size" kludge. -- The usage of runtime->rate in snd_pcm_tick_prepare() in pcm_lib.c was incorrect, regarless of other changes. The impact was that the timer was systematically set to 1 single tick when it needed to be set to typically hundreds of ticks. -- The usage of runtime->sleep_min in snd_pcm_tick_prepare() in pcm_lib.c was incorrect, regarless of other changes. The impact was that the number of ticks for the timer was not properly adjusted up to what sleep_min is documented to mean, when needed. ====================================================================== Relationships ID Summary ---------------------------------------------------------------------- related to 0000946 Early playback DMA IRQ with CMI8738MC6 ... ====================================================================== ---------------------------------------------------------------------- charles_levert - 03-03-05 14:37 ---------------------------------------------------------------------- Attached file "early-irqs.patch" is hereby obsoleted. It is replaced by the following four patches: -- "hz-int-div.0b03.patch": Fix rounded-up integer division bug. -- "rate-sleep-ticks.0b03.patch": Fix bugs with usage of runtime->tick_time. -- "appl_ptr-boundary.0b03.patch": Fix bugs with incorrectly wrapped appl_ptr. -- "early-irqs.0b03.patch": Fix bugs with early IRQs mishandling, missing silence fill, and wrong timing calculations. The bulk of changes can be found in the last patch, but their number has been significantly reduced in some places. E.g., snd_pcm_update_hw_ptr() is no longer modified and snd_pcm_update_hw_ptr_interrupt() is much less modified. The existing boundary-rounding intervals are no longer changed so user space should not show the possibility of being adversely affected. The OSS changes are also no longer required. ---------------------------------------------------------------------- perex - 03-03-05 15:03 ---------------------------------------------------------------------- It seems that hz-int-div.0b03.patch and rate-sleep-ticks.0b03.patch contains same patch but different description.... Issue History Date Modified Username Field Change ====================================================================== 02-28-05 21:26 charles_levert New Issue 02-28-05 21:26 charles_levert Kernel Version => 2.4.22 02-28-05 21:29 charles_levert File Added: early-irqs.patch 03-01-05 09:36 perex Relationship added related to 0000946 03-01-05 09:40 perex Note Added: 0003755 03-01-05 11:15 charles_levert Note Added: 0003757 03-02-05 09:22 Clemens LadischNote Added: 0003761 03-02-05 13:01 charles_levert Note Added: 0003768 03-02-05 13:39 perex Note Added: 0003771 03-02-05 14:53 charles_levert Note Added: 0003776 03-03-05 14:21 charles_levert File Added: hz-int-div.0b03.patch 03-03-05 14:22 charles_levert File Added: rate-sleep-ticks.0b03.patch 03-03-05 14:23 charles_levert File Added: appl_ptr-boundary.0b03.patch 03-03-05 14:23 charles_levert File Added: early-irqs.0b03.patch 03-03-05 14:37 charles_levert Note Added: 0003786 03-03-05 15:03 perex Note Added: 0003787 ====================================================================== ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. 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