在 2019-10-06日的 22:44 +0800，Icenowy Zheng写道： > 在 2019-10-03四的 09:53 +0530，Jagan Teki写道： > > Hi Wens, > > > > On Tue, Oct 1, 2019 at 1:34 PM Icenowy Zheng <icenowy@xxxxxxx> > > wrote: > > > This reverts commit 62e7511a4f4dcf07f753893d3424decd9466c98b. > > > > > > This commit, although claimed as a refactor, in fact changed the > > > formula. > > > > > > By expanding the original formula, we can find that the const 10 > > > is > > > not > > > substracted, instead it's added to the value (because 10 is > > > negative > > > when calculating hsa, and hsa itself is negative when calculating > > > hblk). > > > This breaks the similar pattern to other formulas, so restoring > > > the > > > original formula is more proper. > > > > > > Signed-off-by: Icenowy Zheng <icenowy@xxxxxxx> > > > --- > > > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 9 ++------- > > > 1 file changed, 2 insertions(+), 7 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > index 2d3e822a7739..cb5fd19c0d0d 100644 > > > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c > > > @@ -577,14 +577,9 @@ static void sun6i_dsi_setup_timings(struct > > > sun6i_dsi *dsi, > > > (mode->hsync_start - mode->hdisplay) * > > > Bpp - HFP_PACKET_OVERHEAD); > > > > > > /* > > > - * The blanking is set using a sync event (4 > > > bytes) > > > - * and a blanking packet (4 bytes + payload + 2 > > > - * bytes). Its minimal size is therefore 10 > > > bytes. > > > + * hblk seems to be the line + porches length. > > > */ > > > -#define HBLK_PACKET_OVERHEAD 10 > > > - hblk = max((unsigned int)HBLK_PACKET_OVERHEAD, > > > - (mode->htotal - (mode->hsync_end - > > > mode- > > > > hsync_start)) * Bpp - > > > - HBLK_PACKET_OVERHEAD); > > > + hblk = mode->htotal * Bpp - hsa; > > > > The original formula is correct according to BSP [1] and work with > > my > > panels which I have tested before. May be the horizontal timings on > > panels you have leads to negative value. > > Do you tested the same timing with BSP kernel? > > It's quite difficult to get a negative value here, because the value > is > quite big (includes mode->hdisplay * Bpp). By re-checking with the BSP source code, I found that the constant in the HFP formula is indeed wrong -- it should be 16, not 6. > > Strangely, only change the formula here back makes the timing > translated from FEX file works (tested on PineTab and PinePhone > production ver). The translation rule is from [1]. > > So I still insist on the patch because it's needed by experiment. > > [1] http://linux-sunxi.org/LCD > > > [1] > > https://github.com/ayufan-pine64/linux-pine64/blob/my-hacks-1.2-with-drm/drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c#L919 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
