On 2023-05-19 14:17:30, Jessica Zhang wrote: > Currently, slice_count is being used to calculate word count and > pkt_per_line. In downstream, these values are calculated using slice per > packet, which is not the same as slice_count. > > Slice count represents the number of soft slices per interface, and its > value will not always match that of slice per packet. For example, it is > possible to have cases where there are multiple soft slices per interface > but the panel specifies only one slice per packet. > > Thus, use the default value of one slice per packet and remove slice_count > from the aforementioned calculations. > > Fixes: 08802f515c3c ("drm/msm/dsi: Add support for DSC configuration") > Fixes: bc6b6ff8135c ("drm/msm/dsi: Use DSC slice(s) packet size to compute > word count") > Signed-off-by: Jessica Zhang <quic_jessz...@quicinc.com> > --- > drivers/gpu/drm/msm/dsi/dsi_host.c | 24 ++++++++++++++---------- > 1 file changed, 14 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c > b/drivers/gpu/drm/msm/dsi/dsi_host.c > index d04f8bbd707d..8c8858ee59ec 100644 > --- a/drivers/gpu/drm/msm/dsi/dsi_host.c > +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c > @@ -866,18 +866,15 @@ static void dsi_update_dsc_timing(struct msm_dsi_host > *msm_host, bool is_cmd_mod > */ > slice_per_intf = msm_dsc_get_slices_per_intf(dsc, hdisplay); > > - /* > - * If slice_count is greater than slice_per_intf > - * then default to 1. This can happen during partial > - * update. > - */ > - 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 = total_bytes_per_intf % 3; > - pkt_per_line = slice_per_intf / dsc->slice_count; > + > + /* > + * Default to 1 slice_per_pkt, so pkt_per_line will be equal to > + * slice per intf. > + */ > + pkt_per_line = slice_per_intf;
Same as the comment below, perhaps it is a good idea to clarify in the comment here that the original value wa *multiplied by* slice_per_pkt? Otherwise this default of 1 is "invisible". Alternatively we could have a `const slice_per_pkt = 1;` at the top, and have the comment (the elaborate one from below) there? - Marijn > > if (is_cmd_mode) /* packet data type */ > reg = > DSI_COMMAND_COMPRESSION_MODE_CTRL_STREAM0_DATATYPE(MIPI_DSI_DCS_LONG_WRITE); > @@ -1001,7 +998,14 @@ static void dsi_timing_setup(struct msm_dsi_host > *msm_host, bool is_bonded_dsi) > if (!msm_host->dsc) > wc = hdisplay * dsi_get_bpp(msm_host->format) / 8 + 1; > else > - wc = msm_host->dsc->slice_chunk_size * > msm_host->dsc->slice_count + 1; > + /* > + * When DSC is enabled, WC = slice_chunk_size * > slice_per_packet + 1. > + * Currently, the driver only supports default value of > slice_per_packet = 1 > + * > + * TODO: Expand mipi_dsi_device struct to hold > slice_per_packet info > + * and adjust DSC math to account for > slice_per_packet. > + */ > + wc = msm_host->dsc->slice_chunk_size + 1; > > dsi_write(msm_host, REG_DSI_CMD_MDP_STREAM0_CTRL, > DSI_CMD_MDP_STREAM0_CTRL_WORD_COUNT(wc) | > > -- > 2.40.1 >