From: Takashi Iwai <tiwai@suse.de>
To: Florian Fuchs <fuchsfl@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
linux-sound@vger.kernel.org, Kees Cook <kees@kernel.org>,
Markus Elfring <elfring@users.sourceforge.net>,
Adrian McMenamin <adrianmcmenamin@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ALSA: sh: aica: Fix spu_memset() stride
Date: Fri, 23 Oct 2026 15:41:43 +0200 [thread overview]
Message-ID: <87a4o4a608.wl-tiwai@suse.de> (raw)
In-Reply-To: <20261022163241.2504922-1-fuchsfl@gmail.com>
On Thu, 22 Oct 2026 18:32:41 +0200,
Florian Fuchs wrote:
>
> spu_memset() writes one 32-bit word per iteration, but advances the
> destination offset by only one byte. spu_reset() calls it with
> 0x200000 / 4 words to clear the 2 MiB of sound RAM, so:
>
> - three out of four writel() calls target an unaligned address. The
> SH4 can't do that. Each one traps and is emulated by the unaligned
> access fixup. This call to spu_memset() causes 393216 unaligned
> accesses, visible in /proc/cpu/alignment.
> - the clear covered only about 512 KiB of sound RAM, not 2 MiB.
>
> Advance the offset by the size of the written word, to clear the full
> sound RAM using aligned writes.
>
> Fixes: 198de43d758c ("[ALSA] Add ALSA support for the SEGA Dreamcast PCM device")
> Signed-off-by: Florian Fuchs <fuchsfl@gmail.com>
Applied now. Thanks.
Takashi
prev parent reply other threads:[~2026-10-23 13:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-22 16:32 [PATCH] ALSA: sh: aica: Fix spu_memset() stride Florian Fuchs
2026-10-22 20:48 ` Adrian McMenamin
2026-10-23 13:41 ` Takashi Iwai [this message]
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