On 8/2/23 10:39, neil.armstrong@xxxxxxxxxx wrote:
Hi Marek,
Hi,
On 13/07/2023 20:28, Marek Vasut wrote:
<snip>
MIPI_DSI_MODE_VIDEO_NO_HFP means the HBP period is just skipped by
DSIM.
Maybe there is a need for new set of flags which differentiate
between HBP skipped (i.e. NO HBP) and HBP LP11 ?
No, the section of the MIPI DSI spec I posted below clearly states
there are two options:
1) send blanking packets during those periods
2) transition to LP11 during those periods
There is no 3rd option in the spec of not doing both like what you
are suggesting. So DSIM should also be only transitioning to LP11
during those periods if its not sending the blanking packets with
those flags set.
So, there is no need for any new set of flags to differentiate.
The flags and their interpretation is correct in MSM driver. I cannot
comment on what exactly DSIM does with those flags.
How do you explain the comment in include/drm/drm_mipi_dsi.h:
128 /* disable hback-porch area */
129 #define MIPI_DSI_MODE_VIDEO_NO_HBP BIT(6)
Can you specify how you determined those flags were needed on DSIM ? a
vendor tree ? a datasheet ?
The following upstream commit:
996e1defca344 ("drm: exynos: dsi: Fix MIPI_DSI*_NO_* mode flags")
In the meantime, we should revert this patch because it regresses some Qcom
based platforms until we figure out what's missing to make DSIM based
boards
happy.
I'll send a revert change afterwards.
That change would break existing use case on i.MX8M then, I disagree
with that revert.
