From mboxrd@z Thu Jan 1 00:00:00 1970 From: rct@frus.com (Bob Tracy) Subject: Re: [alsa-devel] [regression] 2.6.25-rc4 snd-es18xx broken on Alpha Date: Tue, 1 Apr 2008 15:26:05 -0500 (CDT) Message-ID: <20080401202605.70554DBA2@gherkin.frus.com> References: <47F279E7.60801@uwo.ca> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <47F279E7.60801@uwo.ca> "from Tyson Whitehead at Apr 1, 2008 02:07:35 pm" Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Tyson Whitehead Cc: Bob Tracy , Rene Herman , Michael Cree , Takashi Iwai , ALSA devel , linux-kernel@vger.kernel.org, Ivan Kokshaysky , linux-alpha@vger.kernel.org, Krzysztof Helt Tyson Whitehead wrote: > Okay. I finally got everything tested on my Miata. Unless I missed > something, the es1888_init routine only gets compiled in with > CONFIG_ALPHA_MIATA. The current arch/alpha/kernel/Makefile build logic shows es1888.o built as part of CONFIG_ALPHA_GENERIC, but if that option isn't enabled, then enabling any of the following configuration options will cause es1888.o to be built: CONFIG_ALPHA_DP264 CONFIG_ALPHA_SHARK CONFIG_ALPHA_MIATA > As I've been using the debian generic kernel (i.e., > CONFIG_ALPHA_GENERIC), I have never relied on this routine for anything. > > I did discover, however, when I compiled my own kernel (2.6.25-rc5) with > CONFIG_ALPHA_MIATA, things stopped working. Specifically, I no longer > got any interupts (with or without the es1888_init patch and with or > without the alternative es188xx interupt patch) associated with either > the builtin sound card (es1888) or the IDE controller (CMD646). Interesting. I *seldom* use the Debian generic kernel. It's available, and I install updated versions when they are released, but all of my testing has been with kernels built from the standard kernel.org sources with CONFIG_ALPHA_MIATA enabled. > With CONFIG_ALPHA_GENERIC I only get one interupt with the es18xx driver > unless I applied to "alternative interupt" handling code. Further, > sometime between 2.6.14 and 2.6.16, mpg321 (using the alsa driver) > started generating "Bad page state in process 'mpg321' ... Trying to fix > it up, but a reboot is needed" kernel messages. This is consistent with what I remember you reporting when we were looking at this back in the 2.6.14 timeframe. I was reporting the "bad page state" problems with 2.6.22-rc6 and -rc7. In my case, the trigger was a different application, but only happened when snd_es18xx was loaded. Hugh Dickins suggested it was a regression introduced in 2.6.15 that I had managed to successfully avoid tripping on :-). The analysis went something like this: sound/isa/es18xx.c: snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV, ... led us to sound/core/memalloc.c: res = dma_alloc_coherent(dev, PAGE_SIZE << pg, dma, gfp_flags); where __GFP_COMP was carefully included in gfp_flags to avoid the kinds of problems I was seeing (replacing the pre-2.6.15 use of PageReserved). Hugh said we could blame him or Nick for removing the special PageReserved usage, or the Alpha for ignoring gfp_flags in the following: #define dma_alloc_coherent(dev, size, addr, gfp) \ pci_alloc_consistent(alpha_gendev_to_pci(dev), size, addr) The workaround (until the official patch was issued) was a small patch against arch/alpha/kernel/pci_iommu.c:pci_alloc_consistent() that replaced "gfp_t gfp = GFP_ATOMIC;" with "gfp_t gfp = GFP_ATOMIC|__GFP_COMP;". That eliminated the "bad page state" errors for me, and I don't recall what the official patch was. -- ------------------------------------------------------------------------ Bob Tracy | "I was a beta tester for dirt. They never did rct@frus.com | get all the bugs out." - Steve McGrew on /. ------------------------------------------------------------------------