I tested the i.MX8M Nano EVK with the NXP supplied MIPI-DSI adapter,
which uses an ADV7535 MIPI-DSI to HDMI converter. I found that a few
modes were working, but in many modes my monitor stayed dark.
This series fixes the Samsung DSIM bridge driver to bring up a few more
modes:
The driver read the rate of the PLL ref clock only during probe.
However, if the clock is re-parented to the VIDEO_PLL, changes to the
pixel clock have an effect on the PLL ref clock. Therefore, the driver
must read and potentially update the PLL ref clock on every modeset.
I also found that the rounding mode of the porches and active area has
an effect on the working modes. If the driver rounds up instead of
rounding down and be calculates them in Hz instead of kHz, more modes
start to work.
The following table shows the modes that were working in my test without
this patch set and the modes that are working now:
| Mode | Before | Now |
| 1920x1080-60.00 | X | X |
| 1920x1080-59.94 | | X |
| 1920x1080-50.00 | | X |
| 1920x1080-30.00 | | X |
| 1920x1080-29.97 | | X |
| 1920x1080-25.00 | | X |
| 1920x1080-24.00 | | |
| 1920x1080-23.98 | | |
| 1680x1050-59.88 | | X |
| 1280x1024-75.03 | X | X |
| 1280x1024-60.02 | X | X |
| 1200x960-59.99 | | X |
| 1152x864-75.00 | X | X |
| 1280x720-60.00 | | |
| 1280x720-59.94 | | |
| 1280x720-50.00 | | X |
| 1024x768-75.03 | | X |
| 1024x768-60.00 | | X |
| 800x600-75.00 | X | X |
| 800x600-60.32 | X | X |
| 720x576-50.00 | X | X |
| 720x480-60.00 | | |
| 720x480-59.94 | X | |
| 640x480-75.00 | X | X |
| 640x480-60.00 | | X |
| 640x480-59.94 | | X |
| 720x400-70.08 | | |
Interestingly, the 720x480-59.94 mode stopped working. However, I am
able to bring up the 720x480 modes by manually hacking the active area
(hsa) to 40 and carefully adjusting the clocks, but something still
seems to be off.
Unfortunately, a few more modes are still not working at all. The NXP
downstream kernel has some quirks to handle some of the modes especially
wrt. to the porches, but I cannot figure out, what the driver should
actually do in these cases. Maybe there is still an error in the
calculation of the porches and someone at NXP can chime in.
Michael
Signed-off-by: Michael Tretter <[email protected]>
---
Changes in v2:
- Specify limits for the PLL input clock in samsung_dsim_driver_data
- Rephrase/clarify commit messages
- Link to v1: https://lore.kernel.org/r/[email protected]
---
Marco Felsch (1):
drm/bridge: samsung-dsim: add more mipi-dsi device debug information
Michael Tretter (4):
drm/bridge: samsung-dsim: reread ref clock before configuring PLL
drm/bridge: samsung-dsim: update PLL reference clock
drm/bridge: samsung-dsim: adjust porches by rounding up
drm/bridge: samsung-dsim: calculate porches in Hz
drivers/gpu/drm/bridge/samsung-dsim.c | 54 +++++++++++++++++++++++++++--------
include/drm/bridge/samsung-dsim.h | 3 ++
2 files changed, 45 insertions(+), 12 deletions(-)
---
base-commit: b78b18fb8ee19f7a05f20c3abc865b3bfe182884
change-id: 20230818-samsung-dsim-42346444bce5
Best regards,
--
Michael Tretter <[email protected]>
Calculating the byte_clk in kHz is imprecise for a hs_clock of 55687500
Hz, which may be used with a pixel clock of 74.25 MHz with mode
1920x1080-30.
Fix the calculation by using HZ instead of kHZ.
This requires to change the type to u64 to prevent overflows of the
integer type.
Reviewed-by: Adam Ford <[email protected]> #imx8mm-beacon
Tested-by: Adam Ford <[email protected]> #imx8mm-beacon
Tested-by: Frieder Schrempf <[email protected]> # Kontron BL i.MX8MM + Waveshare 10.1inch HDMI LCD (E)
Reviewed-by: Marco Felsch <[email protected]>
Signed-off-by: Michael Tretter <[email protected]>
---
Changes in v2: None
---
drivers/gpu/drm/bridge/samsung-dsim.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index 714e1e833606..63a0d8dbe37c 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -986,10 +986,12 @@ static void samsung_dsim_set_display_mode(struct samsung_dsim *dsi)
u32 reg;
if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO) {
- int byte_clk_khz = dsi->hs_clock / 1000 / 8;
- int hfp = DIV_ROUND_UP((m->hsync_start - m->hdisplay) * byte_clk_khz, m->clock);
- int hbp = DIV_ROUND_UP((m->htotal - m->hsync_end) * byte_clk_khz, m->clock);
- int hsa = DIV_ROUND_UP((m->hsync_end - m->hsync_start) * byte_clk_khz, m->clock);
+ u64 byte_clk = dsi->hs_clock / 8;
+ u64 pix_clk = m->clock * 1000;
+
+ int hfp = DIV64_U64_ROUND_UP((m->hsync_start - m->hdisplay) * byte_clk, pix_clk);
+ int hbp = DIV64_U64_ROUND_UP((m->htotal - m->hsync_end) * byte_clk, pix_clk);
+ int hsa = DIV64_U64_ROUND_UP((m->hsync_end - m->hsync_start) * byte_clk, pix_clk);
/* remove packet overhead when possible */
hfp = max(hfp - 6, 0);
--
2.39.2
From: Marco Felsch <[email protected]>
Since the MIPI configuration can be changed on demand it is very useful
to print more MIPI settings during the MIPI device attach step.
Signed-off-by: Marco Felsch <[email protected]>
Reviewed-by: Adam Ford <[email protected]> #imx8mm-beacon
Tested-by: Adam Ford <[email protected]> #imx8mm-beacon
Reviewed-by: Inki Dae <[email protected]>
Acked-by: Inki Dae <[email protected]>
Tested-by: Frieder Schrempf <[email protected]> # Kontron BL i.MX8MM + Waveshare 10.1inch HDMI LCD (E)
Reviewed-by: Marco Felsch <[email protected]>
Signed-off-by: Michael Tretter <[email protected]>
---
Changes in v2: None
---
drivers/gpu/drm/bridge/samsung-dsim.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index cf777bdb25d2..3e8ee9d73a72 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1712,7 +1712,10 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
return ret;
}
- DRM_DEV_INFO(dev, "Attached %s device\n", device->name);
+ DRM_DEV_INFO(dev, "Attached %s device (lanes:%d bpp:%d mode-flags:0x%lx)\n",
+ device->name, device->lanes,
+ mipi_dsi_pixel_format_to_bpp(device->format),
+ device->mode_flags);
drm_bridge_add(&dsi->bridge);
--
2.39.2
On 06.10.2023 17:07, Michael Tretter wrote:
> I tested the i.MX8M Nano EVK with the NXP supplied MIPI-DSI adapter,
> which uses an ADV7535 MIPI-DSI to HDMI converter. I found that a few
> modes were working, but in many modes my monitor stayed dark.
>
> This series fixes the Samsung DSIM bridge driver to bring up a few more
> modes:
>
> The driver read the rate of the PLL ref clock only during probe.
> However, if the clock is re-parented to the VIDEO_PLL, changes to the
> pixel clock have an effect on the PLL ref clock. Therefore, the driver
> must read and potentially update the PLL ref clock on every modeset.
>
> I also found that the rounding mode of the porches and active area has
> an effect on the working modes. If the driver rounds up instead of
> rounding down and be calculates them in Hz instead of kHz, more modes
> start to work.
>
> The following table shows the modes that were working in my test without
> this patch set and the modes that are working now:
>
> | Mode | Before | Now |
> | 1920x1080-60.00 | X | X |
> | 1920x1080-59.94 | | X |
> | 1920x1080-50.00 | | X |
> | 1920x1080-30.00 | | X |
> | 1920x1080-29.97 | | X |
> | 1920x1080-25.00 | | X |
> | 1920x1080-24.00 | | |
> | 1920x1080-23.98 | | |
> | 1680x1050-59.88 | | X |
> | 1280x1024-75.03 | X | X |
> | 1280x1024-60.02 | X | X |
> | 1200x960-59.99 | | X |
> | 1152x864-75.00 | X | X |
> | 1280x720-60.00 | | |
> | 1280x720-59.94 | | |
> | 1280x720-50.00 | | X |
> | 1024x768-75.03 | | X |
> | 1024x768-60.00 | | X |
> | 800x600-75.00 | X | X |
> | 800x600-60.32 | X | X |
> | 720x576-50.00 | X | X |
> | 720x480-60.00 | | |
> | 720x480-59.94 | X | |
> | 640x480-75.00 | X | X |
> | 640x480-60.00 | | X |
> | 640x480-59.94 | | X |
> | 720x400-70.08 | | |
>
> Interestingly, the 720x480-59.94 mode stopped working. However, I am
> able to bring up the 720x480 modes by manually hacking the active area
> (hsa) to 40 and carefully adjusting the clocks, but something still
> seems to be off.
>
> Unfortunately, a few more modes are still not working at all. The NXP
> downstream kernel has some quirks to handle some of the modes especially
> wrt. to the porches, but I cannot figure out, what the driver should
> actually do in these cases. Maybe there is still an error in the
> calculation of the porches and someone at NXP can chime in.
>
> Michael
>
> Signed-off-by: Michael Tretter <[email protected]>
All my Exynos-based test boards with DSI display panels still work fine
with this patchset.
Feel free to add:
Tested-by: Marek Szyprowski <[email protected]>
> ---
> Changes in v2:
> - Specify limits for the PLL input clock in samsung_dsim_driver_data
> - Rephrase/clarify commit messages
> - Link to v1: https://lore.kernel.org/r/[email protected]
>
> ---
> Marco Felsch (1):
> drm/bridge: samsung-dsim: add more mipi-dsi device debug information
>
> Michael Tretter (4):
> drm/bridge: samsung-dsim: reread ref clock before configuring PLL
> drm/bridge: samsung-dsim: update PLL reference clock
> drm/bridge: samsung-dsim: adjust porches by rounding up
> drm/bridge: samsung-dsim: calculate porches in Hz
>
> drivers/gpu/drm/bridge/samsung-dsim.c | 54 +++++++++++++++++++++++++++--------
> include/drm/bridge/samsung-dsim.h | 3 ++
> 2 files changed, 45 insertions(+), 12 deletions(-)
> ---
> base-commit: b78b18fb8ee19f7a05f20c3abc865b3bfe182884
> change-id: 20230818-samsung-dsim-42346444bce5
>
> Best regards,
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
Hi,
On Fri, 06 Oct 2023 17:07:02 +0200, Michael Tretter wrote:
> I tested the i.MX8M Nano EVK with the NXP supplied MIPI-DSI adapter,
> which uses an ADV7535 MIPI-DSI to HDMI converter. I found that a few
> modes were working, but in many modes my monitor stayed dark.
>
> This series fixes the Samsung DSIM bridge driver to bring up a few more
> modes:
>
> [...]
Thanks, Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next)
[1/5] drm/bridge: samsung-dsim: add more mipi-dsi device debug information
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=3683182a7254f728778452814abe2437a12502c3
[2/5] drm/bridge: samsung-dsim: reread ref clock before configuring PLL
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=eb26c6ab2a11e6c595ee88ce30c7de9578d957aa
[3/5] drm/bridge: samsung-dsim: update PLL reference clock
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=846307185f0ffbbe6b34d53b97c31c0fc392cff0
[4/5] drm/bridge: samsung-dsim: adjust porches by rounding up
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=198e54282ae560958e64328fe8f72893661b9e8b
[5/5] drm/bridge: samsung-dsim: calculate porches in Hz
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=6acb691824933535219dfd94d9d97c922f5593d2
--
Neil