Hi,
On 05/11/2019 08:55, Takashi Iwai wrote:
> Hi,
>
> while recently working on the ALSA memory allocator API cleanup, I
> noticed that dw-hdmi bridge driver seems doing weird about the buffer
> management. It pre-allocates the usual device buffers fully at the
> probe time, while each stream allocates the buffer via the vmalloc
> helpers and replaces with it at each open.
>
> I guess it's no expected behavior? It's basically a full waste of
> resources, and the vmalloc buffer isn't guaranteed to work well for
> mmap on every architecture.
>
> Below is the patch to address it. Can anyone check whether this still
> works?
I don't have the setup to check, but this has been pushed by Russell I Added in CC.
I also added the imx maintainer since it's (AFAIK) only used on iMX SoCs.
Neil
>
> Since I have a cleanup series and this is involved, I'd like to take
> the fix through my tree once after it's confirmed (and get ACK if
> possible).
>
>
> Thanks!
>
> Takashi
>
> -- 8< --
> From: Takashi Iwai <tiwai@xxxxxxx>
> Subject: [PATCH] drm/bridge: dw-hdmi: Fix the incorrect buffer allocations
>
> The driver sets up the buffer preallocation with SNDRV_DMA_TYPE_DEV,
> while it re-allocates and releases vmalloc pages. This is not only a
> lot of waste resources but also causes the mmap malfunction.
>
> Change / drop the vmalloc-related code and use the standard buffer
> allocation / release code instead.
>
> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> ---
> drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
> index 2b7539701b42..8fe7a6e8ff94 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-ahb-audio.c
> @@ -384,15 +384,14 @@ static int dw_hdmi_close(struct snd_pcm_substream *substream)
>
> static int dw_hdmi_hw_free(struct snd_pcm_substream *substream)
> {
> - return snd_pcm_lib_free_vmalloc_buffer(substream);
> + return snd_pcm_lib_free_pages(substream);
> }
>
> static int dw_hdmi_hw_params(struct snd_pcm_substream *substream,
> struct snd_pcm_hw_params *params)
> {
> /* Allocate the PCM runtime buffer, which is exposed to userspace. */
> - return snd_pcm_lib_alloc_vmalloc_buffer(substream,
> - params_buffer_bytes(params));
> + return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
> }
>
> static int dw_hdmi_prepare(struct snd_pcm_substream *substream)
> @@ -511,7 +510,6 @@ static const struct snd_pcm_ops snd_dw_hdmi_ops = {
> .prepare = dw_hdmi_prepare,
> .trigger = dw_hdmi_trigger,
> .pointer = dw_hdmi_pointer,
> - .page = snd_pcm_lib_get_vmalloc_page,
> };
>
> static int snd_dw_hdmi_probe(struct platform_device *pdev)
>
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