| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <62abad94-fe4a-2505-506d-6e4bc6b425ff@collabora.com>
Date: Wed, 25 May 2022 14:26:57 +0200
From: AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>
To: Guillaume Ranquet <granquet@...libre.com>,
Chun-Kuang Hu <chunkuang.hu@...nel.org>,
Philipp Zabel <p.zabel@...gutronix.de>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
Matthias Brugger <matthias.bgg@...il.com>,
Chunfeng Yun <chunfeng.yun@...iatek.com>,
Kishon Vijay Abraham I <kishon@...com>,
Vinod Koul <vkoul@...nel.org>, Helge Deller <deller@....de>,
CK Hu <ck.hu@...iatek.com>, Jitao shi <jitao.shi@...iatek.com>
Cc: Markus Schneider-Pargmann <msp@...libre.com>,
dri-devel@...ts.freedesktop.org,
linux-mediatek@...ts.infradead.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-phy@...ts.infradead.org, linux-fbdev@...r.kernel.org
Subject: Re: [PATCH v10 04/21] drm/edid: Add cea_sad helpers for freq/length
Il 23/05/22 12:47, Guillaume Ranquet ha scritto:
> This patch adds two helper functions that extract the frequency and word
> length from a struct cea_sad.
>
> For these helper functions new defines are added that help translate the
> 'freq' and 'byte2' fields into real numbers.
>
> Signed-off-by: Markus Schneider-Pargmann <msp@...libre.com>
> Signed-off-by: Guillaume Ranquet <granquet@...libre.com>
> ---
> drivers/gpu/drm/drm_edid.c | 74 ++++++++++++++++++++++++++++++++++++++
> include/drm/drm_edid.h | 14 ++++++++
> 2 files changed, 88 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 561f53831e29..61ef1b1c972c 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -4758,6 +4758,80 @@ int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb)
> }
> EXPORT_SYMBOL(drm_edid_to_speaker_allocation);
>
> +/**
> + * drm_cea_sad_get_sample_rate - Extract the sample rate from cea_sad
> + * @sad: Pointer to the cea_sad struct
> + *
> + * Extracts the cea_sad frequency field and returns the sample rate in Hz.
> + *
> + * Return: Sample rate in Hz or a negative errno if parsing failed.
> + */
> +int drm_cea_sad_get_sample_rate(const struct cea_sad *sad)
> +{
> + switch (sad->freq) {
> + case DRM_CEA_SAD_FREQ_32KHZ:
> + return 32000;
> + case DRM_CEA_SAD_FREQ_44KHZ:
> + return 44100;
> + case DRM_CEA_SAD_FREQ_48KHZ:
> + return 48000;
> + case DRM_CEA_SAD_FREQ_88KHZ:
> + return 88200;
> + case DRM_CEA_SAD_FREQ_96KHZ:
> + return 96000;
> + case DRM_CEA_SAD_FREQ_176KHZ:
> + return 176400;
> + case DRM_CEA_SAD_FREQ_192KHZ:
> + return 192000;
> + default:
> + return -EINVAL;
> + }
> +}
> +EXPORT_SYMBOL(drm_cea_sad_get_sample_rate);
> +
> +static bool drm_cea_sad_is_uncompressed(const struct cea_sad *sad)
> +{
> + switch (sad->format) {
> + case HDMI_AUDIO_CODING_TYPE_STREAM:
As far as I know, bit 0 is reserved, so HDMI_AUDIO_CODING_TYPE_STREAM should
never occur here?
> + case HDMI_AUDIO_CODING_TYPE_PCM:
> + return true;
> + default:
> + return false;
> + }
> +}
> +
Also, I think that implementing a drm_cea_sad_get_compressed_max_bitrate()
function should be pretty straightforward... the spec says that this is
8 bits, byte 3 (your byte2) contains the max bitrate divided by 8kHz,
so to extract it, you read byte2 and multiply it by 8000Hz.
/**
* drm_cea_sad_get_compressed_max_bitrate - Extract maximum bitrate
* @sad: Pointer to the cea_sad structure
*
* Extracts the cea_sad byte2 field and returns the maximum bit rate
* of a compressed audio stream.
*
* Note: This function may only be called for compressed audio.
*
* Return: Maximum bitrate of compressed audio stream in bit/s or
* negative number for error
*/
int drm_cea_sad_get_compressed_max_bitrate(const struct cea_sad *sad)
{
if (drm_cea_sad_is_uncompressed(sad)) {
DRM_ERROR("Not supported: tried to get max bitrate for uncompressed format: %u\n",
sad->format);
return -EINVAL;
}
return sad->byte2 * 8000;
}
> +/**
> + * drm_cea_sad_get_uncompressed_word_length - Extract word length
> + * @sad: Pointer to the cea_sad struct
> + *
> + * Extracts the cea_sad byte2 field and returns the word length for an
> + * uncompressed stream.
> + *
> + * Note: This function may only be called for uncompressed audio.
> + *
> + * Return: Word length in bits or a negative errno if parsing failed.
> + */
> +int drm_cea_sad_get_uncompressed_word_length(const struct cea_sad *sad)
> +{
> + if (!drm_cea_sad_is_uncompressed(sad)) {
> + DRM_WARN("Unable to get the uncompressed word length for a compressed format: %u\n",
> + sad->format);
> + return -EINVAL;
> + }
> +
> + switch (sad->byte2) {
> + case DRM_CEA_SAD_UNCOMPRESSED_WORD_16BIT:
> + return 16;
> + case DRM_CEA_SAD_UNCOMPRESSED_WORD_20BIT:
> + return 20;
> + case DRM_CEA_SAD_UNCOMPRESSED_WORD_24BIT:
> + return 24;
> + default:
> + return -EINVAL;
> + }
> +}
> +EXPORT_SYMBOL(drm_cea_sad_get_uncompressed_word_length);
> +
> /**
> * drm_av_sync_delay - compute the HDMI/DP sink audio-video sync delay
> * @connector: connector associated with the HDMI/DP sink
> diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
> index 37c420423625..7a939cb95b38 100644
> --- a/include/drm/drm_edid.h
> +++ b/include/drm/drm_edid.h
> @@ -373,6 +373,18 @@ struct cea_sad {
> u8 byte2;
> };
>
> +#define DRM_CEA_SAD_FREQ_32KHZ BIT(0)
> +#define DRM_CEA_SAD_FREQ_44KHZ BIT(1)
> +#define DRM_CEA_SAD_FREQ_48KHZ BIT(2)
> +#define DRM_CEA_SAD_FREQ_88KHZ BIT(3)
> +#define DRM_CEA_SAD_FREQ_96KHZ BIT(4)
> +#define DRM_CEA_SAD_FREQ_176KHZ BIT(5)
> +#define DRM_CEA_SAD_FREQ_192KHZ BIT(6)
> +
> +#define DRM_CEA_SAD_UNCOMPRESSED_WORD_16BIT BIT(0)
> +#define DRM_CEA_SAD_UNCOMPRESSED_WORD_20BIT BIT(1)
> +#define DRM_CEA_SAD_UNCOMPRESSED_WORD_24BIT BIT(2)
> +
> struct drm_encoder;
> struct drm_connector;
> struct drm_connector_state;
> @@ -380,6 +392,8 @@ struct drm_display_mode;
>
> int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads);
> int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb);
> +int drm_cea_sad_get_sample_rate(const struct cea_sad *sad);
> +int drm_cea_sad_get_uncompressed_word_length(const struct cea_sad *sad);
> int drm_av_sync_delay(struct drm_connector *connector,
> const struct drm_display_mode *mode);
>
Powered by blists - more mailing lists