From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755906Ab3LSQsg (ORCPT ); Thu, 19 Dec 2013 11:48:36 -0500 Received: from mail-wg0-f50.google.com ([74.125.82.50]:59434 "EHLO mail-wg0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755146Ab3LSQsd (ORCPT ); Thu, 19 Dec 2013 11:48:33 -0500 Date: Thu, 19 Dec 2013 16:48:24 +0000 From: Lee Jones To: Takashi Iwai Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linus.walleij@linaro.org, broonie@kernel.org, alsa-devel@alsa-project.org Subject: Re: [PATCH 02/11] ASoC: ab8500: Revert back to find_next_bit() Message-ID: <20131219164824.GA16145@lee--X1> References: <1387468508-12286-1-git-send-email-lee.jones@linaro.org> <1387468508-12286-3-git-send-email-lee.jones@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Commit '166a34d ASoC: ab8500: Fix invalid cast to long pointer' > > rather carelessly converts find_next_bit() to fls() (find last > > bit set), which are not the same. > > Does it break on the real machines? It does, that's how I found the bug. > fls() behaves differently from find_next_bit(), of course, but in this > case, it should work same in the end, since there are at most two > bits. Unfortunately it doesn't work at all. This patch brings audio back to a working state. It took me the best part of a day to track down the issue. :( > > Although this implementation may not be portable, the alternative > > breaks audio on anything using the AB8500 CODEC, which is a much > > greater evil. Besides, this driver will never run on anything > > else. > > > > Cc: Takashi Iwai > > Signed-off-by: Lee Jones > > --- > > sound/soc/codecs/ab8500-codec.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/sound/soc/codecs/ab8500-codec.c b/sound/soc/codecs/ab8500-codec.c > > index 1ad92cb..51ae3e9 100644 > > --- a/sound/soc/codecs/ab8500-codec.c > > +++ b/sound/soc/codecs/ab8500-codec.c > > @@ -2322,7 +2322,7 @@ static int ab8500_codec_set_dai_tdm_slot(struct snd_soc_dai *dai, > > slot = ffs(tx_mask); > > snd_soc_update_bits(codec, AB8500_DASLOTCONF1, mask, slot); > > snd_soc_update_bits(codec, AB8500_DASLOTCONF3, mask, slot); > > - slot = fls(tx_mask); > > + slot = find_next_bit((unsigned long *)&tx_mask, 32, slot + 1); > > snd_soc_update_bits(codec, AB8500_DASLOTCONF2, mask, slot); > > snd_soc_update_bits(codec, AB8500_DASLOTCONF4, mask, slot); > > break; > > @@ -2364,7 +2364,7 @@ static int ab8500_codec_set_dai_tdm_slot(struct snd_soc_dai *dai, > > AB8500_ADSLOTSEL(slot), > > AB8500_MASK_SLOT(slot), > > AB8500_ADSLOTSELX_AD_OUT_TO_SLOT(AB8500_AD_OUT3, slot)); > > - slot = fls(rx_mask); > > + slot = find_next_bit((unsigned long *)&rx_mask, 32, slot + 1); > > snd_soc_update_bits(codec, > > AB8500_ADSLOTSEL(slot), > > AB8500_MASK_SLOT(slot), -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog