On Fri, 31 Mar 2023 at 03:07, Jessica Zhang <quic_jesszhan@xxxxxxxxxxx> wrote:
>
>
>
> On 3/30/2023 4:14 PM, Dmitry Baryshkov wrote:
> > On 31/03/2023 01:49, Jessica Zhang wrote:
> >>
> >>
> >> On 3/29/2023 4:48 PM, Dmitry Baryshkov wrote:
> >>> On 30/03/2023 02:18, Jessica Zhang wrote:
> >>>> Use MSM and DRM DSC helper methods.
> >>>>
> >>>> Signed-off-by: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
> >>>> ---
> >>>> drivers/gpu/drm/msm/dsi/dsi_host.c | 18 ++++++++++++------
> >>>> 1 file changed, 12 insertions(+), 6 deletions(-)
> >>>>
> >>>> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c
> >>>> b/drivers/gpu/drm/msm/dsi/dsi_host.c
> >>>> index 74d38f90398a..7419fe58a941 100644
> >>>> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
> >>>> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
> >>>> @@ -31,6 +31,7 @@
> >>>> #include "msm_kms.h"
> >>>> #include "msm_gem.h"
> >>>> #include "phy/dsi_phy.h"
> >>>> +#include "disp/msm_dsc_helper.h"
> >>>> #define DSI_RESET_TOGGLE_DELAY_MS 20
> >>>> @@ -841,14 +842,14 @@ static void dsi_update_dsc_timing(struct
> >>>> msm_dsi_host *msm_host, bool is_cmd_mod
> >>>> {
> >>>> struct drm_dsc_config *dsc = msm_host->dsc;
> >>>> u32 reg, reg_ctrl, reg_ctrl2;
> >>>> - u32 slice_per_intf, total_bytes_per_intf;
> >>>> + u32 slice_per_intf;
> >>>> u32 pkt_per_line;
> >>>> u32 eol_byte_num;
> >>>> /* first calculate dsc parameters and then program
> >>>> * compress mode registers
> >>>> */
> >>>> - slice_per_intf = DIV_ROUND_UP(hdisplay, dsc->slice_width);
> >>>> + slice_per_intf = msm_dsc_get_slice_per_intf(dsc, hdisplay);
> >>>
> >>> This looks good
> >>>
> >>>> /*
> >>>> * If slice_count is greater than slice_per_intf
> >>>> @@ -858,10 +859,10 @@ static void dsi_update_dsc_timing(struct
> >>>> msm_dsi_host *msm_host, bool is_cmd_mod
> >>>> if (dsc->slice_count > slice_per_intf)
> >>>> dsc->slice_count = 1;
> >>>> - total_bytes_per_intf = dsc->slice_chunk_size * slice_per_intf;
> >>>> + eol_byte_num = msm_dsc_get_eol_byte_num(msm_host->dsc, hdisplay,
> >>>> + dsi_get_bpp(msm_host->format));
> >>>> - eol_byte_num = total_bytes_per_intf % 3;
> >>>> - pkt_per_line = slice_per_intf / dsc->slice_count;
> >>>> + pkt_per_line = slice_per_intf / MSM_DSC_SLICE_PER_PKT;
> >>>
> >>> And for these values the result is definitely changed. Separate patch
> >>> & description please. Just in case, "values per downstream kernel" is
> >>> not a proper description for such changes.
> >>
> >> Hi Dmitry,
> >>
> >> Sure, I can put this into a separate patch.
> >>
> >> The reason this was changed from slice_count to SLICE_PER_PKT was
> >> because slice count and slice per packet aren't always equivalent.
> >> There can be cases where panel configures DSC to have multiple soft
> >> slices per interface, but the panel only specifies 1 slice per packet.
> >
> > Please put this nice description into the commit message. It is exactly
> > what I was looking for!
> >
> > BTW: Do you expect to change MSM_DSC_SLICE_PER_PKT later or it will stay
> > at "1"? If so, it might be easier to drop it and instead add a comment.
>
> MSM_DSC_SLICE_PER_PKT is the default value for panels that don't specify
> a slice_per_pkt value. (Now that I think about it, might be better to
> call it MSM_DSC_DEFAULT_SLICE_PER_PKT instead...)
Note, there is no slice_per_pkt in drm_dsc_config, so we must come up
with another way to pass this data from the panel or to deduce the
value in our driver.
>
> I don't expect it to change in the future, but it's a little more
> readable than just dividing by 1 IMO. If you prefer dropping the macro
> and adding a comment, I'm also okay with that.
There is no need to divide by 1, the value doesn't change. So I'd
probably prefer something like:
/* Default to 1 slice per packet */
if (panel_slice_per_pkt)
pkt_per_line = slice_per_intf / panel_slice_per_pkt;
else
pkt_per_line = slice_per_intf;
Or:
/* Default to 1 slice per packet */
slice_per_pkt = 1;
if (panel_slice_per_pkt)
slice_per_pkt = panel_slice_per_pkt;
pkt_per_line = slice_per_intf / slice_per_pkt;
BTW: could you possibly change 'intf' to 'line' to v2? It seems there
is a mixture of them through the code. If there is a difference
between intf and line which is not yet posted, it's fine to keep the
current code. WDYT?
>
> Thanks,
>
> Jessica Zhang
>
> >
> > Regarding eol_byte_num, probably the best explanation would be that is
> > is a size of a padding rather than a size of a trailer bytes in a line
> > (and thus original calculation was incorrect).
> >
> >>
> >>>
> >>>> if (is_cmd_mode) /* packet data type */
> >>>> reg =
> >>>> DSI_COMMAND_COMPRESSION_MODE_CTRL_STREAM0_DATATYPE(MIPI_DSI_DCS_LONG_WRITE);
> >>>> @@ -911,6 +912,11 @@ static void dsi_timing_setup(struct
> >>>> msm_dsi_host *msm_host, bool is_bonded_dsi)
> >>>> DBG("");
> >>>> + if (msm_host->mode_flags & MIPI_DSI_MODE_VIDEO)
> >>>> + /* Default widebus_en to false for now. */
> >>>> + hdisplay = msm_dsc_get_pclk_per_line(msm_host->dsc,
> >>>> mode->hdisplay,
> >>>> + dsi_get_bpp(msm_host->format));
> >>>> +
> >>>
> >>> This is definitely something new and thus should probably go into a
> >>> separate patch and be described. Also I'm not sure how does that
> >>> interact with the hdisplay-related calculations below, under the
> >>> if(dsc) clause.
> >>
> >> After double-checking the math here, I think this part of the change
> >> is actually wrong. pclk_per_line is essentially doing hdisplay / 3,
> >> which is a repeat of what's being done in the `if (dsc)` block.
> >>
> >> Will replace `hdisplay /= 3` with the pclk_per_line calculation.
> >
> > Thanks!
> >
> >>
> >> Thanks,
> >>
> >> Jessica Zhang
> >>
> >>>
> >>>> /*
> >>>> * For bonded DSI mode, the current DRM mode has
> >>>> * the complete width of the panel. Since, the complete
> >>>> @@ -1759,7 +1765,7 @@ static int dsi_populate_dsc_params(struct
> >>>> msm_dsi_host *msm_host, struct drm_dsc
> >>>> return ret;
> >>>> }
> >>>> - dsc->initial_scale_value = 32;
> >>>> + dsc->initial_scale_value =
> >>>> drm_dsc_calculate_initial_scale_value(dsc);
> >>>
> >>> This is fine, we only support 8bpp where these values match.
> >>>
> >>>> dsc->line_buf_depth = dsc->bits_per_component + 1;
> >>>> return drm_dsc_compute_rc_parameters(dsc);
> >>>>
> >>>
> >>> --
> >>> With best wishes
> >>> Dmitry
> >>>
> >
> > --
> > With best wishes
> > Dmitry
> >
--
With best wishes
Dmitry
