On 6/14/2023 2:43 AM, Marijn Suijten wrote:
On 2023-06-12 16:37:36, 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 <quic_jesszhan@xxxxxxxxxxx>
---
drivers/gpu/drm/msm/dsi/dsi_host.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 744f2398a6d6..8254b06dca85 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -994,6 +994,11 @@ static void dsi_timing_setup(struct msm_dsi_host *msm_host, bool is_bonded_dsi)
dsi_write(msm_host, REG_DSI_CMD_MDP_STREAM0_TOTAL,
DSI_CMD_MDP_STREAM0_TOTAL_H_TOTAL(hdisplay) |
DSI_CMD_MDP_STREAM0_TOTAL_V_TOTAL(mode->vdisplay));
+
+ if (msm_host->cfg_hnd->major == MSM_DSI_VER_MAJOR_6G &&
+ msm_host->cfg_hnd->minor >= MSM_DSI_6G_VER_MINOR_V1_3)
+ dsi_write(msm_host, REG_DSI_CMD_MODE_MDP_CTRL2,
+ DSI_CMD_MODE_MDP_CTRL2_BURST_MODE);
This is not part of the timing setup, and a similar BURST_MODE flag is
enabled for video-mode in dsi_ctrl_config() - should it be moved there?
Hi Marijn,
Sure, I can move the change to dsi_ctrl_enable() instead.
(There is a dsi_sw_reset() in between the calls to dsi_timing_setup()
and dsi_ctrl_cfg())
Note that that function sets up the CMD_CFG0 and CMD_CFG1 register, with
the former having a very similar layout to MDP_CTRL2... is there
documentation outlining the difference?
I see what you mean, but unfortunately I'm not able to give you any
documentation about the differences between them.
FWIW, I think the macros in dsi.xml.h should give you a sense of what's
within the registers and the slight differences between them.
Thanks,
Jessica Zhang
- Marijn
}
}
---
base-commit: dd969f852ba4c66938c71889e826aa8e5300d2f2
change-id: 20230608-b4-add-burst-mode-a5bb144069fa
Best regards,
--
Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
