Hi, On Wed 13 Nov 19, 11:04, Patrik Jakobsson wrote: > On Tue, Nov 12, 2019 at 4:50 PM Paul Kocialkowski > wrote: > > > > Hi, > > > > On Tue 12 Nov 19, 16:11, Paul Kocialkowski wrote: > > > Hi, > > > > > > On Tue 12 Nov 19, 11:20, Patrik Jakobsson wrote: > > > > On Thu, Nov 7, 2019 at 4:30 PM Paul Kocialkowski > > > > wrote: > > > > > > > > > > psbfb_probe performs an evaluation of the required size from the stolen > > > > > GTT memory, but gets it wrong in two distinct ways: > > > > > - The resulting size must be page-size-aligned; > > > > > - The size to allocate is derived from the surface dimensions, not the fb > > > > > dimensions. > > > > > > > > > > When two connectors are connected with different modes, the smallest will > > > > > be stored in the fb dimensions, but the size that needs to be allocated must > > > > > match the largest (surface) dimensions. This is what is used in the actual > > > > > allocation code. > > > > > > > > > > Fix this by correcting the evaluation to conform to the two points above. > > > > > It allows correctly switching to 16bpp when one connector is e.g. 1920x1080 > > > > > and the other is 1024x768. > > > > > > > > > > Signed-off-by: Paul Kocialkowski > > > > > --- > > > > > drivers/gpu/drm/gma500/framebuffer.c | 8 ++++++-- > > > > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > > > > > > > diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c > > > > > index 218f3bb15276..90237abee088 100644 > > > > > --- a/drivers/gpu/drm/gma500/framebuffer.c > > > > > +++ b/drivers/gpu/drm/gma500/framebuffer.c > > > > > @@ -462,6 +462,7 @@ static int psbfb_probe(struct drm_fb_helper *helper, > > > > > container_of(helper, struct psb_fbdev, psb_fb_helper); > > > > > struct drm_device *dev = psb_fbdev->psb_fb_helper.dev; > > > > > struct drm_psb_private *dev_priv = dev->dev_private; > > > > > + unsigned int fb_size; > > > > > int bytespp; > > > > > > > > > > bytespp = sizes->surface_bpp / 8; > > > > > @@ -471,8 +472,11 @@ static int psbfb_probe(struct drm_fb_helper *helper, > > > > > /* If the mode will not fit in 32bit then switch to 16bit to get > > > > > a console on full resolution. The X mode setting server will > > > > > allocate its own 32bit GEM framebuffer */ > > > > > - if (ALIGN(sizes->fb_width * bytespp, 64) * sizes->fb_height > > > > > > - dev_priv->vram_stolen_size) { > > > > > + fb_size = ALIGN(sizes->surface_width * bytespp, 64) * > > > > > + sizes->surface_height; > > > > > + fb_size = ALIGN(fb_size, PAGE_SIZE); > > > > > + > > > > > + if (fb_size > dev_priv->vram_stolen_size) { > > > > > > > > psb_gtt_alloc_range() already aligns by PAGE_SIZE for us. Looks like > > > > we align a couple of times extra for luck. This needs cleaning up > > > > instead of adding even more aligns. > > > > > > I'm not sure this is really for luck. As far as I can see, we need to do it > > > properly for this size estimation since it's the final size that will be > > > allocated (and thus needs to be available in whole). > > Ok now I understand what you meant. Actually vram_stolen_size is > always page aligned so fb_size doesn't need any page alignment here. I'm a bit confused here, what about the case where: unaligned fb_size < dev_priv->vram_stolen_size but aligned fb_size > dev_priv->vram_stolen_size ? Granted, it's a corner case, but I don't follow the logic of comparing aligned and unaligned sizes: it feels a bit like comparing two values of different units. > There is also no need to align for psbfb_create() since it also takes > care of this. > > > > > > > For the other times there is explicit alignment, they seem justified too: > > > - in psb_gem_create: it is common to pass the aligned size when creating the > > > associated GEM object with drm_gem_object_init, even though it's probably not > > > crucial given that this is not where allocation actually happens; > > > - in psbfb_create: the full size is apparently only really used to memset 0 > > > the allocated buffer. I think this makes sense for security reasons (and not > > > leak previous contents in the additional space required for alignment). > > What I would prefer is to have a single place where the alignment is > made so any hardware requirements would be transparent to the rest of > the code. Mhh, I thought that psbfb_create needs to be aware of the alignment in the form of the pitch_lines variable to decide which 2d accel method can be used or not (depending on associated alignment requirements). I guess this makes for another reason to ditch the accelerated 2d accel support. > Best would be if alignment is only made in psb_gtt_alloc_range() and > then store the actual size in struct gtt_range. That way we can just > pass along that value to memset() and drm_gem_object_init() without > caring about how it is adjusted. > > > > > > > What strikes me however is that each call to psb_gtt_alloc_range takes the > > > alignment as a parameter when it's really always PAGE_SIZE, so it should > > > probably just be hardcoded in the call to allocate_resource. > > This is a remnant from trying to add support for 2D and/or overlay > planes (don't really remember). Doesn't matter if it stays or goes > away. > > > > > > > What do you think? > > I suppose most of this is outside the scope of what you're trying to > do so we can just leave it as is and I can clean it up later. I guess my main change here was to switch from sizes->fb_width/height to sizes->surface_width/height anyway, yes. I can totally live without the final PAGE_SIZE align for fb_size too (even though I think it makes sense). Feel free to let me know what you'd like to receive as a v2 here and I'll do that :) > > > > > > > Your size calculation looks correct and indeed makes my 1024x600 + > > > > 1920x1080 setup actually display something, but for some reason I get > > > > an incorrect panning on the smaller screen and stale data on the > > > > surface only visible by the larger CRTC. Any idea what's going on? > > > > > > I'm not seeing this immediately, but I definitely have something strange > > > after having printed more lines than the smallest display can handle or > > > scrolling, where more than the actual size of the fb is used. > > > > > > Maybe this is related to using the PowerVR-accelerated fb ops, that aren't > > > quite ready for this use case? > > > > > > I'll give it a try with psbfb_roll_ops and psbfb_unaccel_ops instead to see > > > if it changes something for me. Maybe it would help for you too? > > > > Some quick feedback about that: > > - psbfb_unaccel_ops gives a correct result where the scrolling area is bound > > to the smallest display; > > Yes, this also works correctly for me. > > > - psbfb_roll_ops gives a working scrolling but bound to the largest display > > (so the current shell line becomes invisible on the smallest one eventually); > > It's not panning at all for me. I never really found gtt rolling to be > useful. It's a neat trick but I didn't have a problem with console > scrolling speed to begin with. I might just remove it. Yeah, I also don't understand what the hype of accelerating fbdev ops is about. I guess it could have been useful back when there were serious users of fbdev in userspace (aka directfb) but that's not really where things are going today. For console usage, I also find the software method fast enough. > > - psbfb_ops gives the same issue as above and seems to add artifacts on top. > > Did you try this on CDV? There's only 2D acceleration on Poulsbo and Oaktrail. I tried this one on Poulsbo (the other gma500 platform I have around). > > > > There's probably limited interest in working on that aspect on our side though. > > I'd be interested to know if it affects the issue you're seeing though. > > Focus on your requirements and I'll look at the rest. Sounds good to me, thanks a lot! I'll do according to what you'd like for a v2. Cheers, Paul > -Patrik > > > > > Cheers, > > > > Paul > > > > > I suspect that the generic implementation is already bullet-proof for these > > > kinds of use case. > > > > > > Cheers and thanks for the feedback, > > > > > > Paul > > > > > > > > > > > > sizes->surface_bpp = 16; > > > > > sizes->surface_depth = 16; > > > > > } > > > > > -- > > > > > 2.23.0 > > > > > > > > > > > -- > > > Paul Kocialkowski, Bootlin > > > Embedded Linux and kernel engineering > > > https://bootlin.com > > > > > > > > -- > > Paul Kocialkowski, Bootlin > > Embedded Linux and kernel engineering > > https://bootlin.com -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com