On Fri, Jun 21, 2019 at 2:51 AM Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Jun 18, 2019 at 8:15 PM Chen-Yu Tsai <wens@xxxxxxxx> wrote: > > > > On Tue, Jun 18, 2019 at 8:11 PM Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > On Tue, Jun 18, 2019 at 5:13 PM Chen-Yu Tsai <wens@xxxxxxxx> wrote: > > > > > > > > On Tue, Jun 18, 2019 at 6:51 PM Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > > On Fri, Jun 14, 2019 at 8:15 PM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > > > > > > > > > On Fri, Jun 14, 2019 at 12:03:13PM +0530, Jagan Teki wrote: > > > > > > > On Thu, Jun 13, 2019 at 6:56 PM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > On Wed, Jun 05, 2019 at 01:17:11PM +0530, Jagan Teki wrote: > > > > > > > > > On Tue, Jun 4, 2019 at 3:30 PM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > On Wed, May 29, 2019 at 11:44:56PM +0530, Jagan Teki wrote: > > > > > > > > > > > On Wed, May 29, 2019 at 8:24 PM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > > > > > On Fri, May 24, 2019 at 03:48:51PM +0530, Jagan Teki wrote: > > > > > > > > > > > > > On Fri, May 24, 2019 at 2:04 AM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Mon, May 20, 2019 at 02:33:08PM +0530, Jagan Teki wrote: > > > > > > > > > > > > > > > According to "DRM kernel-internal display mode structure" in > > > > > > > > > > > > > > > include/drm/drm_modes.h the current driver is trying to include > > > > > > > > > > > > > > > sync timings along with front porch value while checking and > > > > > > > > > > > > > > > computing drq set bits in non-burst mode. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > mode->hsync_end - mode->hdisplay => horizontal front porch + sync > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > With adding additional sync timings, the dsi controller leads to > > > > > > > > > > > > > > > wrong drq set bits for "bananapi,s070wv20-ct16" panel which indeed > > > > > > > > > > > > > > > trigger panel flip_done timed out as: > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > WARNING: CPU: 0 PID: 31 at drivers/gpu/drm/drm_atomic_helper.c:1429 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0 > > > > > > > > > > > > > > > [CRTC:46:crtc-0] vblank wait timed out > > > > > > > > > > > > > > > Modules linked in: > > > > > > > > > > > > > > > CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 5.1.0-next-20190514-00026-g01f0c75b902d-dirty #13 > > > > > > > > > > > > > > > Hardware name: Allwinner sun8i Family > > > > > > > > > > > > > > > Workqueue: events deferred_probe_work_func > > > > > > > > > > > > > > > [<c010ed54>] (unwind_backtrace) from [<c010b76c>] (show_stack+0x10/0x14) > > > > > > > > > > > > > > > [<c010b76c>] (show_stack) from [<c0688c70>] (dump_stack+0x84/0x98) > > > > > > > > > > > > > > > [<c0688c70>] (dump_stack) from [<c011d9e4>] (__warn+0xfc/0x114) > > > > > > > > > > > > > > > [<c011d9e4>] (__warn) from [<c011da40>] (warn_slowpath_fmt+0x44/0x68) > > > > > > > > > > > > > > > [<c011da40>] (warn_slowpath_fmt) from [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0) > > > > > > > > > > > > > > > [<c040cd50>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c040e694>] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c) > > > > > > > > > > > > > > > [<c040e694>] (drm_atomic_helper_commit_tail_rpm) from [<c040e4dc>] (commit_tail+0x40/0x6c) > > > > > > > > > > > > > > > [<c040e4dc>] (commit_tail) from [<c040e5cc>] (drm_atomic_helper_commit+0xbc/0x128) > > > > > > > > > > > > > > > [<c040e5cc>] (drm_atomic_helper_commit) from [<c0411b64>] (restore_fbdev_mode_atomic+0x1cc/0x1dc) > > > > > > > > > > > > > > > [<c0411b64>] (restore_fbdev_mode_atomic) from [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0xa0) > > > > > > > > > > > > > > > [<c04156f8>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c0415774>] (drm_fb_helper_set_par+0x30/0x54) > > > > > > > > > > > > > > > [<c0415774>] (drm_fb_helper_set_par) from [<c03ad450>] (fbcon_init+0x560/0x5ac) > > > > > > > > > > > > > > > [<c03ad450>] (fbcon_init) from [<c03eb8a0>] (visual_init+0xbc/0x104) > > > > > > > > > > > > > > > [<c03eb8a0>] (visual_init) from [<c03ed1b8>] (do_bind_con_driver+0x1b0/0x390) > > > > > > > > > > > > > > > [<c03ed1b8>] (do_bind_con_driver) from [<c03ed780>] (do_take_over_console+0x13c/0x1c4) > > > > > > > > > > > > > > > [<c03ed780>] (do_take_over_console) from [<c03ad800>] (do_fbcon_takeover+0x74/0xcc) > > > > > > > > > > > > > > > [<c03ad800>] (do_fbcon_takeover) from [<c013c9c8>] (notifier_call_chain+0x44/0x84) > > > > > > > > > > > > > > > [<c013c9c8>] (notifier_call_chain) from [<c013cd20>] (__blocking_notifier_call_chain+0x48/0x60) > > > > > > > > > > > > > > > [<c013cd20>] (__blocking_notifier_call_chain) from [<c013cd50>] (blocking_notifier_call_chain+0x18/0x20) > > > > > > > > > > > > > > > [<c013cd50>] (blocking_notifier_call_chain) from [<c03a6e44>] (register_framebuffer+0x1e0/0x2f8) > > > > > > > > > > > > > > > [<c03a6e44>] (register_framebuffer) from [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c) > > > > > > > > > > > > > > > [<c04153c0>] (__drm_fb_helper_initial_config_and_unlock) from [<c04158c8>] (drm_fbdev_client_hotplug+0xe8/0x1b8) > > > > > > > > > > > > > > > [<c04158c8>] (drm_fbdev_client_hotplug) from [<c0415a20>] (drm_fbdev_generic_setup+0x88/0x118) > > > > > > > > > > > > > > > [<c0415a20>] (drm_fbdev_generic_setup) from [<c043f060>] (sun4i_drv_bind+0x128/0x160) > > > > > > > > > > > > > > > [<c043f060>] (sun4i_drv_bind) from [<c044b598>] (try_to_bring_up_master+0x164/0x1a0) > > > > > > > > > > > > > > > [<c044b598>] (try_to_bring_up_master) from [<c044b668>] (__component_add+0x94/0x140) > > > > > > > > > > > > > > > [<c044b668>] (__component_add) from [<c0445e1c>] (sun6i_dsi_probe+0x144/0x234) > > > > > > > > > > > > > > > [<c0445e1c>] (sun6i_dsi_probe) from [<c0452ef4>] (platform_drv_probe+0x48/0x9c) > > > > > > > > > > > > > > > [<c0452ef4>] (platform_drv_probe) from [<c04512cc>] (really_probe+0x1dc/0x2c8) > > > > > > > > > > > > > > > [<c04512cc>] (really_probe) from [<c0451518>] (driver_probe_device+0x60/0x160) > > > > > > > > > > > > > > > [<c0451518>] (driver_probe_device) from [<c044f7a4>] (bus_for_each_drv+0x74/0xb8) > > > > > > > > > > > > > > > [<c044f7a4>] (bus_for_each_drv) from [<c045107c>] (__device_attach+0xd0/0x13c) > > > > > > > > > > > > > > > [<c045107c>] (__device_attach) from [<c0450474>] (bus_probe_device+0x84/0x8c) > > > > > > > > > > > > > > > [<c0450474>] (bus_probe_device) from [<c0450900>] (deferred_probe_work_func+0x64/0x90) > > > > > > > > > > > > > > > [<c0450900>] (deferred_probe_work_func) from [<c0135970>] (process_one_work+0x204/0x420) > > > > > > > > > > > > > > > [<c0135970>] (process_one_work) from [<c013690c>] (worker_thread+0x274/0x5a0) > > > > > > > > > > > > > > > [<c013690c>] (worker_thread) from [<c013b3d8>] (kthread+0x11c/0x14c) > > > > > > > > > > > > > > > [<c013b3d8>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c) > > > > > > > > > > > > > > > Exception stack(0xde539fb0 to 0xde539ff8) > > > > > > > > > > > > > > > 9fa0: 00000000 00000000 00000000 00000000 > > > > > > > > > > > > > > > 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > > > > > > > > > > > > > > > 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 > > > > > > > > > > > > > > > ---[ end trace b57eb1e5c64c6b8b ]--- > > > > > > > > > > > > > > > random: fast init done > > > > > > > > > > > > > > > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:46:crtc-0] flip_done timed out > > > > > > > > > > > > > > > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:48:DSI-1] flip_done timed out > > > > > > > > > > > > > > > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:30:plane-0] flip_done timed out > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > But according to Allwinner A33, A64 BSP code [1] [3] the TCON DRQ for > > > > > > > > > > > > > > > non-burst DSI mode can be computed based on "horizontal front porch" > > > > > > > > > > > > > > > value only (no sync timings included). > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Detailed evidence for drq set bits based on A33 BSP [1] [2] > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > => panel->lcd_ht - panel->lcd_x - panel->lcd_hbp - 20 > > > > > > > > > > > > > > > => (tt->hor_front_porch + lcdp->panel_info.lcd_hbp + > > > > > > > > > > > > > > > lcdp->panel_info.lcd_x) - panel->lcd_x - panel->lcd_hbp - 20 > > > > > > > > > > > > > > > => tt->hor_front_porch - 20 > > > > > > > > > > > > > > > > > > > > > > > > > > > > The thing is, while your explanation on the DRM side is sound, > > > > > > > > > > > > > > Allwinner has been using the hbp field of their panel description to > > > > > > > > > > > > > > store what DRM calls the backporch and the sync period. > > > > > > > > > > > > > > > > > > > > > > > > > > Exactly, hbp = backporch + sync > > > > > > > > > > > > > https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp/de/disp_lcd.c#L2046 > > > > > > > > > > > > > > > > > > > > > > > > > > And the above computation is rely on that as well. If you can see the > > > > > > > > > > > > > final out of the above computation you can get the front porch value > > > > > > > > > > > > > (w/o sync ) > > > > > > > > > > > > > > > > > > > > > > > > As I was saying, you are explaining it well for DRM, but in order for > > > > > > > > > > > > your last formula (the one coming from the BSP) to make sense, you > > > > > > > > > > > > have to explain that the horizontal back porch for Allwinner contains > > > > > > > > > > > > the sync period, otherwise your expansion of lcd_ht doesn't make > > > > > > > > > > > > sense. > > > > > > > > > > > > > > > > > > > > > > I'm not sure why we need to take care of back porch since the formula > > > > > > > > > > > clearly evaluating a result as front porch, without sync timing (as > > > > > > > > > > > current code included this sync), I keep the hbp and trying to > > > > > > > > > > > substitute the lcd_ht value so the end result would cancel hbp. > > > > > > > > > > > > > > > > > > > > Because it changes how lcd_ht expands. In the DRM case, it will expand > > > > > > > > > > to the displayed area, the front porch, the sync period and the back > > > > > > > > > > porch. > > > > > > > > > > > > > > > > > > > > In your case, you expand it to the displayed area, the front porch and > > > > > > > > > > the back porch, precisely because in Allwinner's case, the back porch > > > > > > > > > > has the sync period. > > > > > > > > > > > > > > > > > > I understand the point, but technically it matter about the final > > > > > > > > > computation result. May be we can even manage the same computation in > > > > > > > > > back porch, but I'm not sure. Since the final output doesn't involve > > > > > > > > > any sync length, why we can include that ie what I'm not sure. > > > > > > > > > > > > > > > > We have the following formula: > > > > > > > > lcd_ht - lcd_x - lcd_hbp - 20 > > > > > > > > > > > > > > > > Using the concepts as they are defined in DRM, this expands to: > > > > > > > > x + hbp + hsync + hfp - x - hbp - 20 > > > > > > > > > > > > > > Here is diff between allwinner hbp vs hbp in DRM. > > > > > > > > > > > > > > Say hbp in DRM can call it hbackporch, so > > > > > > > > > > > > > > => x + hbackporch + hsync + hfp - -x - hbp - 20 > > > > > > > > > > > > > > (and here we need to substitute hbp formula from allwinner since the > > > > > > > actual equation would coming from there > > > > > > > https://github.com/BPI-SINOVOIP/BPI-M2M-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp/de/disp_lcd.c#L2046) > > > > > > > > > > > > And this is precisely what needs to be said, with an explanation about > > > > > > where that hor_back_porch is being used later on, and what impact it > > > > > > could have. > > > > > > > > > > Yes, it an equation and the mathematical equations can be substitute > > > > > to variety kind I did agree with that, whether you can use hbackporch > > > > > or not or use another-way the final resulting value is equivalent to > > > > > the value of front porch. In that case we can solve based on what I > > > > > explained above. If you still dought me, please run BSP and check the > > > > > resulting value on this check, you can get the front porch value. > > > > > > > > Maxime is not doubting you. He is saying that you need to include the > > > > detailed explanation in your commit log, and not just reference pieces > > > > of code. This is separate from the requirement of having a correct patch. > > > > > > > > Providing just a mathematical formula isn't enough either, because it > > > > is not clear to the average reader which term expanded into what. A > > > > > > Not sure whether you see my commit log on this version or not. Each > > > one has it's own way of providing the details and explanation and at > > > the end people in ML should understand it. I'm not proving a simple > > > formula here (like I did it in initial version) instead I'm giving all > > > the respective information along with the bug log, and the bsp links > > > where it comes from etc. This is easier way for everyone to > > > understand. > > > > I did, and I'm telling you it's not easy to follow. > > > > > Just a bit to explain what I've mentioned in the log. > > > > > > Paragraph 1: > > > > > > " > > > According to "DRM kernel-internal display mode structure" in > > > include/drm/drm_modes.h the current driver is trying to include > > > sync timings along with front porch value while checking and > > > computing drq set bits in non-burst mode. > > > > > > mode->hsync_end - mode->hdisplay => horizontal front porch + sync > > > " > > > > > > This paragraph explains what the existing code is using according to > > > DRM, which indeed help new users to understand by providing > > > include/drm/drm_modes.h file. > > > > This at the beginning makes no sense. It would be better placed with > > the formula after > > the bug report > > > > > Paragraph 2: > > > > > > " > > > With adding additional sync timings, the dsi controller leads to > > > wrong drq set bits for "bananapi,s070wv20-ct16" panel which indeed > > > trigger panel flip_done timed out as: > > > " > > > > > > This paragraph explains what is the relevant issue with existing change. > > > > > > Paragraph 3: > > > > > > BUG or WARNING log > > > > You should lead with these two. These explain "why". > > > > > Paragraph 4: > > > > > > " > > > But according to Allwinner A33, A64 BSP code [1] [3] the TCON DRQ for > > > non-burst DSI mode can be computed based on "horizontal front porch" > > > value only (no sync timings included). > > > " > > > > > > This paragraph explains what is BSP is using compared with mainline. > > > > > > Paragraph 5: > > > > > > " > > > Detailed evidence for drq set bits based on A33 BSP [1] [2] > > > > > > => panel->lcd_ht - panel->lcd_x - panel->lcd_hbp - 20 > > > => (tt->hor_front_porch + lcdp->panel_info.lcd_hbp + > > > lcdp->panel_info.lcd_x) - panel->lcd_x - panel->lcd_hbp - 20 > > > => tt->hor_front_porch - 20 > > > " > > > > > > This paragraph explains the detailed steps of equation evaluation by > > > providing BSP links. > > > > This actually makes it harder to read. For example it takes a couple passes > > to realize lcd_ht expands to the stuff in the parenthesis. All the while I > > still have no idea what all these variables mean or where they came from. > > As I said, please don't ask users to open links and dig through code. > > The main reasons I have included this information and the BSP links > are for future reference, to know the real proofs if anyone would want > to. and even the timeout log. My idea of formula evaluation here just > like what you refer in the diagram in previous mail. I thought > mathematical equations are much easier to understand and provable. Unfortunately the plain-text formatting sometimes doesn't help. Simple text descriptions work better in most cases, diffs in others. You can still include the formula as a reference, but it is better to explain it outright in simple sentences, rather than providing the formula and guiding the reader through it. ChenYu > > You should provide a simple explanation about what went wrong. As I > > mentioned, you could have simply stated that when the driver was > > reimplemented, the DRQ formula (which you can provide in its original > > form) was incorrectly expanded because Allwinner's definition of "hbp" > > is actually "hbp + sync" in DRM terms. That is actually the root cause, > > which I believe is what Maxime wants detailed in the commit log. > > This immediately points out what went wrong and how it went wrong, > > without jumping through hoops. > > > > Again the diagram helps immensely. (Well, maybe not for screen readers.) > > It also directly shows why you replaced hsync_end with hsync_start. > > True, this indeed has different and direct understanding of what went > wrong. thanks for this. > > > > > > Paragraph 6: > > > > > > " > > > Which is mode->hsync_start - mode->hdisplay as per > > > "DRM kernel-internal display mode structure" in include/drm/drm_modes.h > > > " > > > > > > This paragraph give fix details in according to Linux DRM. > > > > Yes, and first you need to understand the formula you gave, which I > > already mentioned is a bit hard. > > > > On the side, going through the code and understanding it actually is quite > > hard as I already did it a couple times before and it was really taxing. > > > > > So, all the explanation which I'm trying to provide here will help to > > > understand, what is the issue with existing code and BUG log, how it > > > handle in BSP, with justification of equations and links where it > > > refers. Please note that I'm providing bug log and before that I've > > > mentioned this timeout because of additional sync. why is the timeout > > > with additional sync time, which I'm unaware since we don't have > > > associated datasheets for this but we have working BSP's to prove > > > that. > > > > > > Frankly, I still didn't understand what I missed here to explain the > > > issue. request for help if you see any issues on this format or > > > information. > > > > The one thing you missed, and that Maxime requested, was how hbp, and > > the misinterpretation of it plays into all of this. In fact the different > > definitions of terms between DRM and Allwinner code / FEX files is what > > led to all this. The rest is, well, somewhat hard to read. I already > > shared my way of explaining everything above. > > Okay, will try to re-arrange the commit in next version. hope this > time will more cleaner. thanks. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
