On 2020-01-10 1:47 p.m., Liu, Zhan wrote: > > >> -----Original Message----- >> From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of >> Christian König >> Sent: 2020/January/10, Friday 10:02 AM >> To: Siqueira, Rodrigo <Rodrigo.Siqueira@xxxxxxx>; amd- >> gfx@xxxxxxxxxxxxxxxxxxxxx >> Cc: Li, Sun peng (Leo) <Sunpeng.Li@xxxxxxx>; Cheng, Tony >> <Tony.Cheng@xxxxxxx>; Tsai, Martin <Martin.Tsai@xxxxxxx>; Lakha, >> Bhawanpreet <Bhawanpreet.Lakha@xxxxxxx>; Wentland, Harry >> <Harry.Wentland@xxxxxxx> >> Subject: Re: [PATCH 39/43] drm/amd/display: Use udelay to avoid context >> switch >> >> Am 10.01.20 um 15:46 schrieb Rodrigo Siqueira: >>> From: Martin Tsai <martin.tsai@xxxxxxx> >>> >>> [why] >>> The rapid msleep operation causes the white line garbage when DAL >>> check flip pending status in SetVidPnSourceVisibility. >>> To execute this msleep will induce context switch, and longer delay >>> could cause worse garbage situation. >>> >>> [how] >>> To replace msleep with udelay. >>> >>> Signed-off-by: Martin Tsai <martin.tsai@xxxxxxx> >>> Reviewed-by: Tony Cheng <Tony.Cheng@xxxxxxx> >>> Acked-by: Harry Wentland <harry.wentland@xxxxxxx> >>> Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx> >>> --- >>> drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c >>> b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c >>> index 89920924a154..0dc652e76848 100644 >>> --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c >>> +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c >>> @@ -1642,9 +1642,9 @@ void dcn20_program_front_end_for_ctx( >>> struct hubp *hubp = pipe->plane_res.hubp; >>> int j = 0; >>> >>> - for (j = 0; j < TIMEOUT_FOR_PIPE_ENABLE_MS >>> + for (j = 0; j < TIMEOUT_FOR_PIPE_ENABLE_MS*1000 >>> && hubp->funcs- >>> hubp_is_flip_pending(hubp); j++) >>> - msleep(1); >>> + udelay(1); >> >> Why not using mdelay() here? > > As far as I know, mdelay() is only defined on Linux side. > > This piece of code is shared by both Linux and Windows, so we have to use a function that's available on both platforms. > It was used here before so we definitely have it defined for Windows as well. >From the commit description it sounds like msleep wasn't tight enough and longer delays lead to issues here, at least on Windows. Martin, Tony, do you have more details about this? Thanks, Harry > Zhan > >> >> Christian. >> >>> } >>> } >>> >> >> _______________________________________________ >> amd-gfx mailing list >> amd-gfx@xxxxxxxxxxxxxxxxxxxxx _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
