During a frame transfer in command mode, there could be frequent
LP11 <-> HS transitions when multiple DCS commands are sent mid-frame or
if the DSI controller is running on slow clock and is throttled. To
minimize frame latency due to these transitions, it is recommended to
send the frame in a single burst.
This feature is supported for DSI 6G 1.3 and above, thus enable burst
mode if supported.
Signed-off-by: Jessica Zhang <[email protected]>
---
Changes in v2:
- Moved MDP_CTRL2 register setting to dsi_ctrl_config() (Dmitry/Marijn)
- Read previous value of MDP_CTRL2 register before writing to it
(Dmitry)
- Link to v1: https://lore.kernel.org/r/[email protected]
---
drivers/gpu/drm/msm/dsi/dsi_host.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 3f6dfb4f9d5a..cdb404885f3c 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -752,6 +752,13 @@ static void dsi_ctrl_enable(struct msm_dsi_host *msm_host,
/* Always insert DCS command */
data |= DSI_CMD_CFG1_INSERT_DCS_COMMAND;
dsi_write(msm_host, REG_DSI_CMD_CFG1, data);
+
+ if (msm_host->cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
+ msm_host->cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V1_3) {
+ data = dsi_read(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2);
+ data |= DSI_CMD_MODE_MDP_CTRL2_BURST_MODE;
+ dsi_write(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2, data);
+ }
}
dsi_write(msm_host, REG_DSI_CMD_DMA_CTRL,
---
base-commit: a0364260213c96f6817f7e85cdce293cb743460f
change-id: 20230608-b4-add-burst-mode-a5bb144069fa
Best regards,
--
Jessica Zhang <[email protected]>
On 27/06/2023 23:31, Jessica Zhang wrote:
> During a frame transfer in command mode, there could be frequent
> LP11 <-> HS transitions when multiple DCS commands are sent mid-frame or
> if the DSI controller is running on slow clock and is throttled. To
> minimize frame latency due to these transitions, it is recommended to
> send the frame in a single burst.
>
> This feature is supported for DSI 6G 1.3 and above, thus enable burst
> mode if supported.
>
> Signed-off-by: Jessica Zhang <[email protected]>
> ---
> Changes in v2:
> - Moved MDP_CTRL2 register setting to dsi_ctrl_config() (Dmitry/Marijn)
> - Read previous value of MDP_CTRL2 register before writing to it
> (Dmitry)
> - Link to v1: https://lore.kernel.org/r/[email protected]
> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 7 +++++++
> 1 file changed, 7 insertions(+)
Reviewed-by: Dmitry Baryshkov <[email protected]>
>
> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
> index 3f6dfb4f9d5a..cdb404885f3c 100644
> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> @@ -752,6 +752,13 @@ static void dsi_ctrl_enable(struct msm_dsi_host *msm_host,
> /* Always insert DCS command */
> data |= DSI_CMD_CFG1_INSERT_DCS_COMMAND;
> dsi_write(msm_host, REG_DSI_CMD_CFG1, data);
> +
> + if (msm_host->cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
> + msm_host->cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V1_3) {
Nit: please intent in future to the same level (vim: "set cino=(0").
> + data = dsi_read(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2);
> + data |= DSI_CMD_MODE_MDP_CTRL2_BURST_MODE;
> + dsi_write(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2, data);
> + }
> }
>
> dsi_write(msm_host, REG_DSI_CMD_DMA_CTRL,
>
> ---
> base-commit: a0364260213c96f6817f7e85cdce293cb743460f
> change-id: 20230608-b4-add-burst-mode-a5bb144069fa
>
> Best regards,
--
With best wishes
Dmitry
On Tue, 27 Jun 2023 13:31:45 -0700, Jessica Zhang wrote:
> During a frame transfer in command mode, there could be frequent
> LP11 <-> HS transitions when multiple DCS commands are sent mid-frame or
> if the DSI controller is running on slow clock and is throttled. To
> minimize frame latency due to these transitions, it is recommended to
> send the frame in a single burst.
>
> This feature is supported for DSI 6G 1.3 and above, thus enable burst
> mode if supported.
>
> [...]
Applied, thanks!
[1/1] drm/msm/dsi: Enable BURST_MODE for command mode for DSI 6G v1.3+
https://gitlab.freedesktop.org/lumag/msm/-/commit/4ac447e89e71
Best regards,
--
Dmitry Baryshkov <[email protected]>