HI Christian While #include <linux/delay.h>, it prompt ..\..\..\..\..\dc\dce\dce_aux.c(31): fatal error C1083: Cannot open include file: 'linux/delay.h': No such file or directory Could you help to check how to include the header of void usleep_range(unsigned long min, unsigned long max); -----Original Message----- From: Zhuo, Qingqing <Qingqing.Zhuo@xxxxxxx> Sent: Thursday, September 17, 2020 9:02 PM To: Koenig, Christian <Christian.Koenig@xxxxxxx>; Alex Deucher <alexdeucher@xxxxxxxxx> Cc: Brol, Eryk <Eryk.Brol@xxxxxxx>; Li, Sun peng (Leo) <Sunpeng.Li@xxxxxxx>; Lakha, Bhawanpreet <Bhawanpreet.Lakha@xxxxxxx>; Siqueira, Rodrigo <Rodrigo.Siqueira@xxxxxxx>; amd-gfx list <amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Zhang, Jinlong <Jinlong.Zhang@xxxxxxx>; Wentland, Harry <Harry.Wentland@xxxxxxx> Subject: RE: [PATCH 04/15] drm/amd/display: Replace msleep with udelay while read edid return defer. [AMD Official Use Only - Internal Distribution Only] Am 17.09.20 um 00:18 schrieb Alex Deucher: >> On Wed, Sep 16, 2020 at 6:16 PM Zhuo, Qingqing <Qingqing.Zhuo@xxxxxxx> wrote: >>> [AMD Official Use Only - Internal Distribution Only] >>> >>>On Wed, Sep 16, 2020 at 3:42 PM Qingqing Zhuo <qingqing.zhuo@xxxxxxx> wrote: >>>> From: jinlong zhang <jinlong.zhang@xxxxxxx> >>>> >>> >[why] >>>>while read edid return defer, then it enter to msleep, but it >>>>actually took more time during msleep, this will cause remaining >>>>edid read fail. >>>> >>>> [how] >>>> Replacing msleep with udelay, it will not take any extra time, edid return pass finally. >>> How long of a delay are we talking about here? Some platforms don't support long udelays and someone will send a patch to change this to msleep. >>> >>> Alex >>> >>> --------------------- >>> >>> Hi Alex, >>> >>> It's between 0-5ms for generic cases, though there exist some dongle workaround cases where we will do 70ms. Would this be a concern? >> I think ARM has a limit of 2ms for udelay. > Yeah, there is even a define somewhere for this. > If you need a delay which is longer than this but still more precise than msleep() then there is the high precision timer sleep as alternative. > I've forgotten the function name to use here, but there was a LWN article about this a few years ago. You just need to google a bit. Hi Alex and Christian, Thanks a lot for the input! Given what's been discussed, I will drop this patch for now. Regards, Lillian > > Regards, > Christian. >> >> Alex >> >>> Thank you, >>> Lillian >>> >>> >>>> Signed-off-by: jinlong zhang <jinlong.zhang@xxxxxxx> >>>> Reviewed-by: Wenjing Liu <Wenjing.Liu@xxxxxxx> >>>> Acked-by: Qingqing Zhuo <qingqing.zhuo@xxxxxxx> >>>> --- >>>> drivers/gpu/drm/amd/display/dc/dce/dce_aux.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c >>>> b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c >>>> index 743042d5905a..cdcad82765e0 100644 >>>> --- a/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c >>>> +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_aux.c >>>> @@ -653,7 +653,7 @@ bool dce_aux_transfer_with_retries(struct ddc_service *ddc, >>>> if ((*payload->reply == AUX_TRANSACTION_REPLY_AUX_DEFER) || >>>> (*payload->reply == AUX_TRANSACTION_REPLY_I2C_OVER_AUX_DEFER)) { >>>> if (payload->defer_delay > 0) >>>> - msleep(payload->defer_delay); >>>> + >>>> + udelay(payload->defer_delay * 1000); >>>> } >>>> } >>>> break; >>>> -- >>>> 2.17.1 >>>> >>>> _______________________________________________ >>>> amd-gfx mailing list >>>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx >>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fl >>>> i >>>> st >>>> s.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&data=02%7C01%7 >>>> C >>>> qi >>>> ngqing.zhuo%40amd.com%7C36c3bee68c28448769fa08d85a884619%7C3dd8961f >>>> e >>>> 48 >>>> 84e608e11a82d994e183d%7C0%7C0%7C637358888627498307&sdata=mynpHp >>>> i >>>> up >>>> J%2FU2o5gZNW%2Bft%2Fg2beFY86%2BzMRWoTZCghQ%3D&reserved=0 >> _______________________________________________ >> amd-gfx mailing list >> amd-gfx@xxxxxxxxxxxxxxxxxxxxx >> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flis >> t >> s.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&data=02%7C01%7CQ >> i >> ngqing.Zhuo%40amd.com%7Cd4acd0d5e65c49a7270f08d85ae37036%7C3dd8961fe4 >> 8 >> 84e608e11a82d994e183d%7C0%7C0%7C637359280197936127&sdata=ahcoCqG9 >> 1 >> EDMNlHNSk4Eimh1azMtRWSX%2BKyHCdpFq1Q%3D&reserved=0 _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx