[PATCH] drm/gma500: Remove GTT roll support

Patrik Jakobsson patrik.r.jakobsson at gmail.com
Wed Oct 28 22:49:13 UTC 2020


On Wed, Oct 28, 2020 at 4:41 PM Daniel Vetter <daniel at ffwll.ch> wrote:
>
> On Wed, Oct 28, 2020 at 3:36 PM Patrik Jakobsson
> <patrik.r.jakobsson at gmail.com> wrote:
> >
> > GTT roll support was used to accelerate fb panning on some machines.
> > Unfortunately this never worked properly with multiple monitors and
> > caused issues on others where the framebuffer wouldn't fit in stolen
> > memory. Let's remove it!
> Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>
> btw I tried to figure out whether the accel code is of any use too,
> and we don't set FBINFO_HWACCEL_COPYAREA, despite that we have an
> accelerated copyarea. So I think we could delete all that code too,
> since essentially unused. And aside of fbcon no one is using these
> acceleration functions anyway.
> -Daniel

Yes, it can also go away. It'll remove quite a bit of code. I'll have a look.

-Patrik

>
> >
> > Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson at gmail.com>
> > ---
> >  drivers/gpu/drm/gma500/framebuffer.c | 96 ++++------------------------
> >  drivers/gpu/drm/gma500/gtt.c         | 52 +--------------
> >  drivers/gpu/drm/gma500/gtt.h         |  3 -
> >  3 files changed, 14 insertions(+), 137 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
> > index 5ede24fb44ae..2d64c58607f5 100644
> > --- a/drivers/gpu/drm/gma500/framebuffer.c
> > +++ b/drivers/gpu/drm/gma500/framebuffer.c
> > @@ -76,27 +76,6 @@ static int psbfb_setcolreg(unsigned regno, unsigned red, unsigned green,
> >         return 0;
> >  }
> >
> > -static int psbfb_pan(struct fb_var_screeninfo *var, struct fb_info *info)
> > -{
> > -       struct drm_fb_helper *fb_helper = info->par;
> > -       struct drm_framebuffer *fb = fb_helper->fb;
> > -       struct drm_device *dev = fb->dev;
> > -       struct gtt_range *gtt = to_gtt_range(fb->obj[0]);
> > -
> > -       /*
> > -        *      We have to poke our nose in here. The core fb code assumes
> > -        *      panning is part of the hardware that can be invoked before
> > -        *      the actual fb is mapped. In our case that isn't quite true.
> > -        */
> > -       if (gtt->npage) {
> > -               /* GTT roll shifts in 4K pages, we need to shift the right
> > -                  number of pages */
> > -               int pages = info->fix.line_length >> 12;
> > -               psb_gtt_roll(dev, gtt, var->yoffset * pages);
> > -       }
> > -        return 0;
> > -}
> > -
> >  static vm_fault_t psbfb_vm_fault(struct vm_fault *vmf)
> >  {
> >         struct vm_area_struct *vma = vmf->vma;
> > @@ -176,17 +155,6 @@ static const struct fb_ops psbfb_ops = {
> >         .fb_sync = psbfb_sync,
> >  };
> >
> > -static const struct fb_ops psbfb_roll_ops = {
> > -       .owner = THIS_MODULE,
> > -       DRM_FB_HELPER_DEFAULT_OPS,
> > -       .fb_setcolreg = psbfb_setcolreg,
> > -       .fb_fillrect = drm_fb_helper_cfb_fillrect,
> > -       .fb_copyarea = drm_fb_helper_cfb_copyarea,
> > -       .fb_imageblit = drm_fb_helper_cfb_imageblit,
> > -       .fb_pan_display = psbfb_pan,
> > -       .fb_mmap = psbfb_mmap,
> > -};
> > -
> >  static const struct fb_ops psbfb_unaccel_ops = {
> >         .owner = THIS_MODULE,
> >         DRM_FB_HELPER_DEFAULT_OPS,
> > @@ -312,8 +280,6 @@ static int psbfb_create(struct drm_fb_helper *fb_helper,
> >         int ret;
> >         struct gtt_range *backing;
> >         u32 bpp, depth;
> > -       int gtt_roll = 0;
> > -       int pitch_lines = 0;
> >
> >         mode_cmd.width = sizes->surface_width;
> >         mode_cmd.height = sizes->surface_height;
> > @@ -324,50 +290,15 @@ static int psbfb_create(struct drm_fb_helper *fb_helper,
> >         if (bpp == 24)
> >                 bpp = 32;
> >
> > -       do {
> > -               /*
> > -                * Acceleration via the GTT requires pitch to be
> > -                * power of two aligned. Preferably page but less
> > -                * is ok with some fonts
> > -                */
> > -               mode_cmd.pitches[0] =  ALIGN(mode_cmd.width * ((bpp + 7) / 8), 4096 >> pitch_lines);
> > -
> > -               size = mode_cmd.pitches[0] * mode_cmd.height;
> > -               size = ALIGN(size, PAGE_SIZE);
> > -
> > -               /* Allocate the fb in the GTT with stolen page backing */
> > -               backing = psbfb_alloc(dev, size);
> > -
> > -               if (pitch_lines)
> > -                       pitch_lines *= 2;
> > -               else
> > -                       pitch_lines = 1;
> > -               gtt_roll++;
> > -       } while (backing == NULL && pitch_lines <= 16);
> > -
> > -       /* The final pitch we accepted if we succeeded */
> > -       pitch_lines /= 2;
> > -
> > -       if (backing == NULL) {
> > -               /*
> > -                *      We couldn't get the space we wanted, fall back to the
> > -                *      display engine requirement instead.  The HW requires
> > -                *      the pitch to be 64 byte aligned
> > -                */
> > -
> > -               gtt_roll = 0;   /* Don't use GTT accelerated scrolling */
> > -               pitch_lines = 64;
> > -
> > -               mode_cmd.pitches[0] =  ALIGN(mode_cmd.width * ((bpp + 7) / 8), 64);
> > -
> > -               size = mode_cmd.pitches[0] * mode_cmd.height;
> > -               size = ALIGN(size, PAGE_SIZE);
> > -
> > -               /* Allocate the framebuffer in the GTT with stolen page backing */
> > -               backing = psbfb_alloc(dev, size);
> > -               if (backing == NULL)
> > -                       return -ENOMEM;
> > -       }
> > +       mode_cmd.pitches[0] = ALIGN(mode_cmd.width * DIV_ROUND_UP(bpp, 8), 64);
> > +
> > +       size = mode_cmd.pitches[0] * mode_cmd.height;
> > +       size = ALIGN(size, PAGE_SIZE);
> > +
> > +       /* Allocate the framebuffer in the GTT with stolen page backing */
> > +       backing = psbfb_alloc(dev, size);
> > +       if (backing == NULL)
> > +               return -ENOMEM;
> >
> >         memset(dev_priv->vram_addr + backing->offset, 0, size);
> >
> > @@ -387,17 +318,14 @@ static int psbfb_create(struct drm_fb_helper *fb_helper,
> >
> >         fb_helper->fb = fb;
> >
> > -       if (dev_priv->ops->accel_2d && pitch_lines > 8) /* 2D engine */
> > +       if (dev_priv->ops->accel_2d)    /* 2D engine */
> >                 info->fbops = &psbfb_ops;
> > -       else if (gtt_roll) {    /* GTT rolling seems best */
> > -               info->fbops = &psbfb_roll_ops;
> > -               info->flags |= FBINFO_HWACCEL_YPAN;
> > -       } else  /* Software */
> > +       else    /* Software */
> >                 info->fbops = &psbfb_unaccel_ops;
> >
> >         info->fix.smem_start = dev->mode_config.fb_base;
> >         info->fix.smem_len = size;
> > -       info->fix.ywrapstep = gtt_roll;
> > +       info->fix.ywrapstep = 0;
> >         info->fix.ypanstep = 0;
> >
> >         /* Accessed stolen memory directly */
> > diff --git a/drivers/gpu/drm/gma500/gtt.c b/drivers/gpu/drm/gma500/gtt.c
> > index 9278bcfad1bf..d246b1f70366 100644
> > --- a/drivers/gpu/drm/gma500/gtt.c
> > +++ b/drivers/gpu/drm/gma500/gtt.c
> > @@ -96,16 +96,12 @@ static int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r,
> >         }
> >
> >         /* Write our page entries into the GTT itself */
> > -       for (i = r->roll; i < r->npage; i++) {
> > -               pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]),
> > -                                      PSB_MMU_CACHED_MEMORY);
> > -               iowrite32(pte, gtt_slot++);
> > -       }
> > -       for (i = 0; i < r->roll; i++) {
> > +       for (i = 0; i < r->npage; i++) {
> >                 pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]),
> >                                        PSB_MMU_CACHED_MEMORY);
> >                 iowrite32(pte, gtt_slot++);
> >         }
> > +
> >         /* Make sure all the entries are set before we return */
> >         ioread32(gtt_slot - 1);
> >
> > @@ -140,49 +136,6 @@ static void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r)
> >         set_pages_array_wb(r->pages, r->npage);
> >  }
> >
> > -/**
> > - *     psb_gtt_roll    -       set scrolling position
> > - *     @dev: our DRM device
> > - *     @r: the gtt mapping we are using
> > - *     @roll: roll offset
> > - *
> > - *     Roll an existing pinned mapping by moving the pages through the GTT.
> > - *     This allows us to implement hardware scrolling on the consoles without
> > - *     a 2D engine
> > - */
> > -void psb_gtt_roll(struct drm_device *dev, struct gtt_range *r, int roll)
> > -{
> > -       u32 __iomem *gtt_slot;
> > -       u32 pte;
> > -       int i;
> > -
> > -       if (roll >= r->npage) {
> > -               WARN_ON(1);
> > -               return;
> > -       }
> > -
> > -       r->roll = roll;
> > -
> > -       /* Not currently in the GTT - no worry we will write the mapping at
> > -          the right position when it gets pinned */
> > -       if (!r->stolen && !r->in_gart)
> > -               return;
> > -
> > -       gtt_slot = psb_gtt_entry(dev, r);
> > -
> > -       for (i = r->roll; i < r->npage; i++) {
> > -               pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]),
> > -                                      PSB_MMU_CACHED_MEMORY);
> > -               iowrite32(pte, gtt_slot++);
> > -       }
> > -       for (i = 0; i < r->roll; i++) {
> > -               pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]),
> > -                                      PSB_MMU_CACHED_MEMORY);
> > -               iowrite32(pte, gtt_slot++);
> > -       }
> > -       ioread32(gtt_slot - 1);
> > -}
> > -
> >  /**
> >   *     psb_gtt_attach_pages    -       attach and pin GEM pages
> >   *     @gt: the gtt range
> > @@ -346,7 +299,6 @@ struct gtt_range *psb_gtt_alloc_range(struct drm_device *dev, int len,
> >         gt->resource.name = name;
> >         gt->stolen = backed;
> >         gt->in_gart = backed;
> > -       gt->roll = 0;
> >         /* Ensure this is set for non GEM objects */
> >         gt->gem.dev = dev;
> >         ret = allocate_resource(dev_priv->gtt_mem, &gt->resource,
> > diff --git a/drivers/gpu/drm/gma500/gtt.h b/drivers/gpu/drm/gma500/gtt.h
> > index 3cf190295ad3..2bf165849ebe 100644
> > --- a/drivers/gpu/drm/gma500/gtt.h
> > +++ b/drivers/gpu/drm/gma500/gtt.h
> > @@ -37,7 +37,6 @@ struct gtt_range {
> >         bool mmapping;                  /* Is mmappable */
> >         struct page **pages;            /* Backing pages if present */
> >         int npage;                      /* Number of backing pages */
> > -       int roll;                       /* Roll applied to the GTT entries */
> >  };
> >
> >  #define to_gtt_range(x) container_of(x, struct gtt_range, gem)
> > @@ -49,7 +48,5 @@ extern void psb_gtt_kref_put(struct gtt_range *gt);
> >  extern void psb_gtt_free_range(struct drm_device *dev, struct gtt_range *gt);
> >  extern int psb_gtt_pin(struct gtt_range *gt);
> >  extern void psb_gtt_unpin(struct gtt_range *gt);
> > -extern void psb_gtt_roll(struct drm_device *dev,
> > -                                       struct gtt_range *gt, int roll);
> >  extern int psb_gtt_restore(struct drm_device *dev);
> >  #endif
> > --
> > 2.28.0
> >
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch


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