> -----Original Message-----
> From: Lee, Shawn C <shawn.c.lee@xxxxxxxxx>
> Sent: Thursday, August 12, 2021 9:13 PM
> To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: Nikula, Jani <jani.nikula@xxxxxxxxx>; ville.syrjala@xxxxxxxxxxxxxxx;
> Kulkarni, Vandita <vandita.kulkarni@xxxxxxxxx>; Chiou, Cooper
> <cooper.chiou@xxxxxxxxx>; Tseng, William <william.tseng@xxxxxxxxx>; Lee,
> Shawn C <shawn.c.lee@xxxxxxxxx>; Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Subject: [v4 3/7] drm/i915/dsi: wait for header and payload credit available
>
> Driver should wait for free header or payload buffer in FIFO.
> It would be good to wait a while for HW to release credit before give it up to
> write to HW. Without sending initailize command sets completely. It would
> caused MIPI display can't light up properly.
>
> Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
> Cc: Vandita Kulkarni <vandita.kulkarni@xxxxxxxxx>
> Cc: Cooper Chiou <cooper.chiou@xxxxxxxxx>
> Cc: William Tseng <william.tseng@xxxxxxxxx>
> Signed-off-by: Lee Shawn C <shawn.c.lee@xxxxxxxxx>
Looks good to me.
Reviewed-by: Vandita Kulkarni <vandita.kulkarni@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/icl_dsi.c | 40 ++++++++++++--------------
> 1 file changed, 19 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c
> b/drivers/gpu/drm/i915/display/icl_dsi.c
> index 43ec7fcd3f5d..1780830d9909 100644
> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> @@ -54,20 +54,28 @@ static int payload_credits_available(struct
> drm_i915_private *dev_priv,
> >> FREE_PLOAD_CREDIT_SHIFT;
> }
>
> -static void wait_for_header_credits(struct drm_i915_private *dev_priv,
> - enum transcoder dsi_trans)
> +static bool wait_for_header_credits(struct drm_i915_private *dev_priv,
> + enum transcoder dsi_trans, int hdr_credit)
> {
> if (wait_for_us(header_credits_available(dev_priv, dsi_trans) >=
> - MAX_HEADER_CREDIT, 100))
> + hdr_credit, 100)) {
> drm_err(&dev_priv->drm, "DSI header credits not
> released\n");
> + return false;
> + }
> +
> + return true;
> }
>
> -static void wait_for_payload_credits(struct drm_i915_private *dev_priv,
> - enum transcoder dsi_trans)
> +static bool wait_for_payload_credits(struct drm_i915_private *dev_priv,
> + enum transcoder dsi_trans, int
> payld_credit)
> {
> if (wait_for_us(payload_credits_available(dev_priv, dsi_trans) >=
> - MAX_PLOAD_CREDIT, 100))
> + payld_credit, 100)) {
> drm_err(&dev_priv->drm, "DSI payload credits not
> released\n");
> + return false;
> + }
> +
> + return true;
> }
>
> static enum transcoder dsi_port_to_transcoder(enum port port) @@ -90,8
> +98,8 @@ static void wait_for_cmds_dispatched_to_panel(struct
> intel_encoder *encoder)
> /* wait for header/payload credits to be released */
> for_each_dsi_port(port, intel_dsi->ports) {
> dsi_trans = dsi_port_to_transcoder(port);
> - wait_for_header_credits(dev_priv, dsi_trans);
> - wait_for_payload_credits(dev_priv, dsi_trans);
> + wait_for_header_credits(dev_priv, dsi_trans,
> MAX_HEADER_CREDIT);
> + wait_for_payload_credits(dev_priv, dsi_trans,
> MAX_PLOAD_CREDIT);
> }
>
> /* send nop DCS command */
> @@ -108,7 +116,7 @@ static void
> wait_for_cmds_dispatched_to_panel(struct intel_encoder *encoder)
> /* wait for header credits to be released */
> for_each_dsi_port(port, intel_dsi->ports) {
> dsi_trans = dsi_port_to_transcoder(port);
> - wait_for_header_credits(dev_priv, dsi_trans);
> + wait_for_header_credits(dev_priv, dsi_trans,
> MAX_HEADER_CREDIT);
> }
>
> /* wait for LP TX in progress bit to be cleared */ @@ -126,18 +134,13
> @@ static bool add_payld_to_queue(struct intel_dsi_host *host, const u8
> *data,
> struct intel_dsi *intel_dsi = host->intel_dsi;
> struct drm_i915_private *dev_priv = to_i915(intel_dsi-
> >base.base.dev);
> enum transcoder dsi_trans = dsi_port_to_transcoder(host->port);
> - int free_credits;
> int i, j;
>
> for (i = 0; i < len; i += 4) {
> u32 tmp = 0;
>
> - free_credits = payload_credits_available(dev_priv,
> dsi_trans);
> - if (free_credits < 1) {
> - drm_err(&dev_priv->drm,
> - "Payload credit not available\n");
> + if (!wait_for_payload_credits(dev_priv, dsi_trans, 1))
> return false;
> - }
>
> for (j = 0; j < min_t(u32, len - i, 4); j++)
> tmp |= *data++ << 8 * j;
> @@ -155,15 +158,10 @@ static int dsi_send_pkt_hdr(struct intel_dsi_host
> *host,
> struct drm_i915_private *dev_priv = to_i915(intel_dsi-
> >base.base.dev);
> enum transcoder dsi_trans = dsi_port_to_transcoder(host->port);
> u32 tmp;
> - int free_credits;
>
> /* check if header credit available */
> - free_credits = header_credits_available(dev_priv, dsi_trans);
> - if (free_credits < 1) {
> - drm_err(&dev_priv->drm,
> - "send pkt header failed, not enough hdr credits\n");
> + if (!wait_for_header_credits(dev_priv, dsi_trans, 1))
> return -1;
> - }
>
> tmp = intel_de_read(dev_priv, DSI_CMD_TXHDR(dsi_trans));
>
> --
> 2.17.1
