On Thu, 25 Apr 2024 at 02:25, Doug Anderson <diand...@google.com> wrote: > > Hi, > > On Wed, Apr 24, 2024 at 3:51 PM Dmitry Baryshkov > <dmitry.barysh...@linaro.org> wrote: > > > > On Thu, 25 Apr 2024 at 01:15, Hsin-Yi Wang <hsi...@google.com> wrote: > > > > > > On Wed, Apr 24, 2024 at 2:49 PM Dmitry Baryshkov > > > <dmitry.barysh...@linaro.org> wrote: > > > > > > > > On Thu, 25 Apr 2024 at 00:04, Doug Anderson <diand...@google.com> wrote: > > > > > > > > > > Hi, > > > > > > > > > > On Tue, Apr 23, 2024 at 2:20 PM Dmitry Baryshkov > > > > > <dmitry.barysh...@linaro.org> wrote: > > > > > > > > > > > > On Tue, Apr 23, 2024 at 01:41:59PM -0700, Doug Anderson wrote: > > > > > > > Hi, > > > > > > > > > > > > > > On Tue, Apr 23, 2024 at 11:10 AM Hsin-Yi Wang <hsi...@google.com> > > > > > > > wrote: > > > > > > > > > > > > > > > > > > > > +#define _INIT_DCS_CMD(...) { \ > > > > > > > > > > > > + .type = INIT_DCS_CMD, \ > > > > > > > > > > > > + .len = sizeof((char[]){__VA_ARGS__}), \ > > > > > > > > > > > > + .data = (char[]){__VA_ARGS__} } > > > > > > > > > > > > + > > > > > > > > > > > > +#define _INIT_DELAY_CMD(...) { \ > > > > > > > > > > > > + .type = DELAY_CMD,\ > > > > > > > > > > > > + .len = sizeof((char[]){__VA_ARGS__}), \ > > > > > > > > > > > > + .data = (char[]){__VA_ARGS__} } > > > > > > > > > > > > > > > > > > > > > > This is the third panel driver using the same appoach. > > > > > > > > > > > Can you use > > > > > > > > > > > mipi_dsi_generic_write_seq() instead of the huge table? > > > > > > > > > > > Or if you prefer > > > > > > > > > > > the table, we should extract this framework to a common > > > > > > > > > > > helper. > > > > > > > > > > > (my preference is shifted towards > > > > > > > > > > > mipi_dsi_generic_write_seq()). > > > > > > > > > > > > > > > > > > > > > The drawback of mipi_dsi_generic_write_seq() is that it can > > > > > > > > > > cause the > > > > > > > > > > kernel size grows a lot since every sequence will be > > > > > > > > > > expanded. > > > > > > > > > > > > > > > > > > > > Similar discussion in here: > > > > > > > > > > https://lore.kernel.org/dri-devel/CAD=FV=Wju3WS45=EpXMUg7FjYDh3-=mvm_js7tf1tsaazbb...@mail.gmail.com/ > > > > > > > > > > > > > > > > > > > > This patch would increase the module size from 157K to 572K. > > > > > > > > > > scripts/bloat-o-meter shows chg +235.95%. > > > > > > > > > > > > > > > > > > > > So maybe the common helper is better regarding the kernel > > > > > > > > > > module size? > > > > > > > > > > > > > > > > > > Yes, let's get a framework done in a useful way. > > > > > > > > > I'd say, drop the _INIT_DELAY_CMD. msleep() and > > > > > > > > > usleep_range() should be > > > > > > > > > used instead (and it's up to the developer to select correct > > > > > > > > > delay > > > > > > > > > function). > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > + > > > > > > > > > > > > +static const struct panel_init_cmd > > > > > > > > > > > > kingdisplay_kd101ne3_init_cmd[] = { > > > > > > > > > > > > + _INIT_DELAY_CMD(50), > > > > > > > > > > > > + _INIT_DCS_CMD(0xE0, 0x00), > > > > > > > > > > > > > > > > > > [skipped the body of the table] > > > > > > > > > > > > > > > > > > > > > + _INIT_DCS_CMD(0x0E, 0x48), > > > > > > > > > > > > + > > > > > > > > > > > > + _INIT_DCS_CMD(0xE0, 0x00), > > > > > > > > > > > > > > > > > > > > > + _INIT_DCS_CMD(0X11), > > > > > > > > > > > > > > > > > > Also, at least this is mipi_dsi_dcs_exit_sleep_mode(). > > > > > > > > > > > > > > > > > > > > > + /* T6: 120ms */ > > > > > > > > > > > > + _INIT_DELAY_CMD(120), > > > > > > > > > > > > + _INIT_DCS_CMD(0X29), > > > > > > > > > > > > > > > > > > And this is mipi_dsi_dcs_set_display_on(). > > > > > > > > > > > > > > > > > > Having a single table enourages people to put known commands > > > > > > > > > into the > > > > > > > > > table, the practice that must be frowned upon and forbidden. > > > > > > > > > > > > > > > > > > We have functions for some of the standard DCS commands. So, > > > > > > > > > maybe > > > > > > > > > instead of adding a single-table based approach we can improve > > > > > > > > > mipi_dsi_generic_write_seq() to reduce the bloat. E.g. by > > > > > > > > > moving the > > > > > > > > > error handling to a common part of enable() / prepare() > > > > > > > > > function. > > > > > > > > > > > > > > > > > > > > > > > > > For this panel, I think it can also refer to how > > > > > > > > panel-kingdisplay-kd097d04.c does. Create the table for init > > > > > > > > cmd data, > > > > > > > > not what operation to use, and use mipi_dsi_generic_write_seq() > > > > > > > > when > > > > > > > > looping through the table. > > > > > > > > > > > > > > Even more similar discussion: > > > > > > > > > > > > > > https://lore.kernel.org/r/CAD=FV=ugdbnvamjzwsovxybgikqcvw9jsrtbxhvg8_97ype...@mail.gmail.com > > > > > > > > > > > > It seems I skipped that thread. > > > > > > > > > > > > I'd still suggest a code-based solution compared to table-based > > > > > > one, for > > > > > > the reasons I've outlined before. Having a tables puts a pressure > > > > > > on the > > > > > > developer to put commands there for which we already have a > > > > > > command-specific function. > > > > > > > > > > The problem is that with these panels that need big init sequences the > > > > > code based solution is _a lot_ bigger. If it were a few bytes or a > > > > > 1-2KB then fine, but when Hsin-Yi measured Linus W's attempt to move > > > > > from a table to code it was 100K difference in code [1]. I would also > > > > > say that having these long init sequences done as separate commands > > > > > encourages people to skip checking the return values of each of the > > > > > transfer functions and I don't love that idea. > > > > > > > > > > It would be ideal if these panels didn't need these long init > > > > > sequences, but I don't have any inside knowledge here saying that they > > > > > could be removed. So assume we can't get rid of the init sequences it > > > > > feels like we have to find some way to make the tables work for at > > > > > least the large chunks of init code and encourage people to make the > > > > > tables readable... > > > > > > > > > > > > I did a quick check on the boe-tv101wum-nl6 driver by converting the > > > > writes to use the following macro: > > > > > > > > #define mipi_dsi_dcs_write_cmd_seq(dsi, cmd, seq...) > > > > \ > > > > do { > > > > \ > > > > static const u8 d[] = { cmd, seq }; > > > > \ > > > > ret = mipi_dsi_dcs_write_buffer(dsi, d, ARRAY_SIZE(d)); > > > > \ > > > > if (ret < 0) > > > > \ > > > > goto err; > > > > \ > > > > } while (0) > > > > > > > > And then at the end of the init funciton having > > > > > > > > err: > > > > dev_err(panel->dev, > > > > "failed to write command %d\n", ret); > > > > return ret; > > > > } > > > > > > > > > > I'm not sure about the coding style rule here, would it be considered > > > unclear that caller of mipi_dsi_dcs_write_cmd_seq() needs to have err > > > block, but the block may not be directly used in that caller and is > > > only jumped from the macro? > > > > I'm also not sure here. It was a quick and dirty test. > > We might as well do something like > > > > ret = mipi_dsi_dcs_write_cmd_seq(dsi, ...); > > if (ret) > > goto err; > > > > all over the place. > > Oh. This is actually very simple to fix and requires no code changes > to clients. :-P We just need to hoist the printing out of the macro > and into "drm_mipi_dsi.c". Let me double-confirm and then I'll post a > patch.
Sounds good. I have converted boe-tv101wum-nl6, ilitek-ili9882t and innolux-p079zca drivers. Once you post your patch I can post those too. -- With best wishes Dmitry