> -----Original Message-----
> From: Nautiyal, Ankit K <[email protected]>
> Sent: Monday, October 12, 2026 9:27 AM
> To: [email protected]; [email protected]
> Cc: [email protected]; [email protected]; Shankar, Uma
> <[email protected]>; [email protected]; Kandpal, Suraj
> <[email protected]>
> Subject: [PATCH v2 01/56] drm/i915/hdmi: Parse FRL max link rate from VBT
>
> From: Vandita Kulkarni <[email protected]>
>
> Parse the maximum FRL link rate from VBT and store it for use during FRL mode
> selection and link training.
There is nothing getting stored here, maybe rephrase it to expose helper to get
FRL max link rate.
>
> v3:
> - Bail out early for VBT version < 237 and resolve the max FRL rate in a
> single switch, handling hdmi_max_frl_rate_valid == 0 up front. (Jani)
> - Drop the intel_bios_hdmi_max_frl_rate() encoder wrapper and take the
> encoder devdata directly. (Jani)
> - Use the standard VBT debug message format. (Jani)
> - Spell FRL and VBT in caps in the subject and debug message. (Suraj, Jani)
> - Move the hdmi_max_frl_rate_valid == 0 comment onto the check it
> describes. (Suraj)
> - Add Bspec reference. (Suraj)
>
> Bspec: XXXXX
Put a valid number here or drop it altogether.
> Signed-off-by: Vandita Kulkarni <[email protected]>
> Signed-off-by: Ankit Nautiyal <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_bios.c | 39 +++++++++++++++++++
> drivers/gpu/drm/i915/display/intel_bios.h | 1 +
> drivers/gpu/drm/i915/display/intel_vbt_defs.h | 7 ++++
> 3 files changed, 47 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_bios.c
> b/drivers/gpu/drm/i915/display/intel_bios.c
> index 7b6a6f8c3cf1..7181237508b3 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.c
> +++ b/drivers/gpu/drm/i915/display/intel_bios.c
> @@ -2788,12 +2788,45 @@ static bool is_port_valid(struct intel_display
> *display,
> enum port port)
> return true;
> }
>
> +int intel_bios_hdmi_max_frl_rate(const struct intel_bios_encoder_data
> +*devdata) {
> + struct intel_display *display = devdata->display;
> +
Add a check for devdata as well to protect against any NULL pointer dereference.
Good to combine that with below check.
> + if (display->vbt.version < 237)
> + return 0;
> +
> + /*
> + * When hdmi_max_frl_rate_valid is 0 the VBT does not specify a
> maximum
> + * FRL rate, so don't use it to limit the FRL rate on FRL-capable
> + * platforms.
> + */
> + if (!devdata->child.hdmi_max_frl_rate_valid)
> + return display->platform.meteorlake ? 12000000 : 0;
> +
Why special casing for MTL, or update the comment.
> + switch (devdata->child.hdmi_max_frl_rate) {
> + default:
> + case HDMI_MAX_FRL_RATE_PLATFORM:
> + return 0;
> + case HDMI_MAX_FRL_RATE_3G:
> + return 3000000;
> + case HDMI_MAX_FRL_RATE_6G:
> + return 6000000;
> + case HDMI_MAX_FRL_RATE_8G:
> + return 8000000;
> + case HDMI_MAX_FRL_RATE_10G:
> + return 10000000;
> + case HDMI_MAX_FRL_RATE_12G:
> + return 12000000;
> + }
> +}
> +
> static void print_ddi_port(const struct intel_bios_encoder_data *devdata) {
> struct intel_display *display = devdata->display;
> bool is_dvi, is_hdmi, is_dp, is_edp, is_dsi, is_crt, supports_typec_usb,
> supports_tbt;
> int dp_boost_level, dp_max_link_rate, hdmi_boost_level,
> hdmi_level_shift,
> max_tmds_clock;
> enum port port;
> + int hdmi_max_frl_rate;
>
> port = intel_bios_encoder_port(devdata);
> if (port == PORT_NONE)
> @@ -2863,6 +2896,12 @@ static void print_ddi_port(const struct
> intel_bios_encoder_data *devdata)
> drm_dbg_kms(display->drm,
> "Port %c VBT DP max link rate: %d\n",
> port_name(port), dp_max_link_rate);
> +
> + hdmi_max_frl_rate = intel_bios_hdmi_max_frl_rate(devdata);
> + if (hdmi_max_frl_rate)
> + drm_dbg_kms(display->drm,
> + "Port %c VBT HDMI max FRL rate: %d\n",
> + port_name(port), hdmi_max_frl_rate);
> }
>
> static void parse_ddi_port(struct intel_bios_encoder_data *devdata) diff
> --git
> a/drivers/gpu/drm/i915/display/intel_bios.h
> b/drivers/gpu/drm/i915/display/intel_bios.h
> index 196b8b3f434f..b89f72d90c1f 100644
> --- a/drivers/gpu/drm/i915/display/intel_bios.h
> +++ b/drivers/gpu/drm/i915/display/intel_bios.h
> @@ -112,6 +112,7 @@ int intel_bios_hdmi_boost_level(const struct
> intel_bios_encoder_data *devdata); int intel_bios_hdmi_ddc_pin(const struct
> intel_bios_encoder_data *devdata); int intel_bios_hdmi_level_shift(const
> struct
> intel_bios_encoder_data *devdata); int intel_bios_hdmi_max_tmds_clock(const
> struct intel_bios_encoder_data *devdata);
> +int intel_bios_hdmi_max_frl_rate(const struct intel_bios_encoder_data
> +*devdata);
>
> void intel_bios_for_each_encoder(struct intel_display *display,
> void (*func)(struct intel_display *display,
> diff --git
> a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> index 0dc13d080e8a..db7484542dc0 100644
> --- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> +++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
> @@ -381,6 +381,13 @@ struct bdb_general_features {
> #define HDMI_MAX_DATA_RATE_340 4 /* 249+
> */
> #define HDMI_MAX_DATA_RATE_300 5 /* 249+
> */
>
> +#define HDMI_MAX_FRL_RATE_PLATFORM 0 /* 237 */
Use 237+ to remain consistent, do it for all.
> +#define HDMI_MAX_FRL_RATE_3G 1 /* 237 */
> +#define HDMI_MAX_FRL_RATE_6G 2 /* 237 */
> +#define HDMI_MAX_FRL_RATE_8G 3 /* 237 */
> +#define HDMI_MAX_FRL_RATE_10G 4 /* 237
> */
> +#define HDMI_MAX_FRL_RATE_12G 5 /* 237
> */
> +
> #define LEGACY_CHILD_DEVICE_CONFIG_SIZE 33
>
> /* DDC Bus DDI Type 155+ */
> --
> 2.50.1
