On Thu, Apr 30, 2020 at 03:54:38PM +0200, Daniel Vetter wrote:
On Thu, Apr 30, 2020 at 09:47:46PM +0800, Xin Ji wrote:
Hi Daniel,
On Thu, Apr 30, 2020 at 03:38:39PM +0200, Daniel Vetter wrote:
On Thu, Apr 30, 2020 at 03:37:31PM +0200, Daniel Vetter wrote:
On Thu, Apr 30, 2020 at 11:36:14AM +0800, Xin Ji wrote:
On Tue, Apr 28, 2020 at 12:05:08PM +0200, Daniel Vetter wrote:
On Fri, Apr 24, 2020 at 08:12:04PM +0800, Nicolas Boichat wrote: > On Fri, Apr 24, 2020 at 2:51 PM Xin Ji xji@analogixsemi.com wrote: > > > > On Thu, Apr 23, 2020 at 07:55:15PM +0800, Nicolas Boichat wrote: > > > Hi, > > > > > > Just commenting on the mode_fixup function that was added in v7. > > > > > [snip] > > > > + /* > > > > + * once illegal timing detected, use default HFP, HSYNC, HBP > > > > + */ > > > > + if (hblanking < HBLANKING_MIN || (hfp < HP_MIN && hbp < HP_MIN)) { > > > > > > should this be adj_hblanking/adj_hfp/adj_hbp? > > NO, need check original HFP and HBP, if they are not legal, driver need > > set default value to adj_hsync, adj_hfp, adj_hbp. > > > > > > > + adj_hsync = SYNC_LEN_DEF; > > > > + adj_hfp = HFP_HBP_DEF; > > > > + adj_hbp = HFP_HBP_DEF; > > > > + vref = adj->clock * 1000 / (adj->htotal * adj->vtotal); > > > > + if (hblanking < HBLANKING_MIN) { > > > > + delta_adj = HBLANKING_MIN - hblanking; > > > > + adj_clock = vref * delta_adj * adj->vtotal; > > > > + adj->clock += DIV_ROUND_UP(adj_clock, 1000); > > > > + } else { > > > > + delta_adj = hblanking - HBLANKING_MIN; > > > > + adj_clock = vref * delta_adj * adj->vtotal; > > > > + adj->clock -= DIV_ROUND_UP(adj_clock, 1000); > > > > + } > > > > + > > > > + DRM_WARN("illegal hblanking timing, use default.\n"); > > > > + DRM_WARN("hfp(%d),hbp(%d),hsync(%d).\n", hfp, hbp, hsync); > > > > > > How likely is it that this mode is going to work? Can you just return > > > false here to reject the mode? > > We want to set the default minimal Hblancking value, then it may display, > > otherwise. If we just return false, there is no display for sure. > > Right, understand your argument. I'm pondering if it's not just better > to reject the mode rather than trying a timing that is definitely > quite different from what the monitor was asking for. No super strong > opinion, I'll let other people on the list weigh in.
Yeah mode_fixup is supposed to be used to adjust the mode in intermediate stages (e.g. if you go from progressive to interlaced only at the end of your pipeline or something like that). It's not meant for adjusting the mode yout actually put out through a hdmi or dp connector. For fixed panels adjusting modes to fit the panel is also fairly common, but not for external outputs.
Since this is a DP bridge I'd say no adjusting, just reject what doesn't fit.
We have found some panel which HBP less than 8, if we reject to adjust video timing, then there is no display. The customer does not accept it, they push us to fix it, the only resolve way is to adjust timing.
Are we talking about external DP screen here, or some built-in panel? For the later case we do a lot of mode adjusting in many drivers ...
I haven't checked, by if our connector type is eDP then this should be all fine.
Ok I read the patch now, you seem to support both. Would it work if we make this adjustement conditional on it being an internal panel only? I think that would be perfect.
-Daniel
Daniel Vetter Software Engineer, Intel Corporation
Based on comments of V8, only keeped eDP built-in panel in V9 version, removed external DP screen support.
Ah even better. Then the above adjusting has my:
Acked-by: Daniel Vetter daniel.vetter@ffwll.ch
Maybe add a comment to the code summarizing the discussion. Definitely needs to be covered in the commit message.
OK, I'll add it in the next serial.
Thanks, Xin
Thanks, Daniel
Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch