video: deferred io sys helpers

From: Magnus Damm <[email protected]>

Change the hecubafb driver and the n411 code to use the new shared sys helpers. This allows us to remove some duplicated code. In the future this driver can setup the "sysdelay" value to delay flushing.

While at it, convert space to tabs for the n411 kconfig entry.

Signed-off-by Magnus Damm <[email protected]>

---

 drivers/video/Kconfig    |   17 +++------
 drivers/video/hecubafb.c |   86 ++--------------------------------------------
 2 files changed, 11 insertions(+), 92 deletions(-)

drivers/video/Kconfig +0 -7

@@ -712,17 +712,12 @@ config FB_EFI
 	  using the EFI framebuffer as your console.
 
 config FB_N411
-       tristate "N411 Apollo/Hecuba devkit support"
-       depends on FB && X86 && MMU
-       select FB_SYS_FILLRECT
-       select FB_SYS_COPYAREA
-       select FB_SYS_IMAGEBLIT
-       select FB_SYS_FOPS
-       select FB_DEFERRED_IO

Quoted 33 lines · Magnus Damm

From: Magnus Damm <[email protected]>

Change the hecubafb driver and the n411 code to use the new shared sys helpers. This allows us to remove some duplicated code. In the future this driver can setup the "sysdelay" value to delay flushing.

While at it, convert space to tabs for the n411 kconfig entry.

Signed-off-by Magnus Damm <[email protected]>

---

 drivers/video/Kconfig    |   17 +++------
 drivers/video/hecubafb.c |   86 ++--------------------------------------------
 2 files changed, 11 insertions(+), 92 deletions(-)

drivers/video/Kconfig 2008-12-22 14:06:31.000000000 +0900 renamed from drivers/video/Kconfig +1 -11

@@ -712,17 +712,12 @@ config FB_EFI
        using the EFI framebuffer as your console.
 
 config FB_N411
-       tristate "N411 Apollo/Hecuba devkit support"
-       depends on FB && X86 && MMU
-       select FB_SYS_FILLRECT
-       select FB_SYS_COPYAREA
-       select FB_SYS_IMAGEBLIT
-       select FB_SYS_FOPS
-       select FB_DEFERRED_IO
-       select FB_HECUBA
-       help
-         This enables support for the Apollo display controller in its
-         Hecuba form using the n411 devkit.
+     tristate "N411 Apollo/Hecuba devkit support"

drivers/video/Kconfig 2008-12-22 14:06:31.000000000 +0900 config FB_EFI · line 720

Quoted 5 lines

drivers/video/Kconfig 2008-12-22 14:06:31.000000000 +0900 renamed from drivers/video/Kconfig +5 -0

+     depends on FB && X86 && MMU
+     select FB_HECUBA
+     help
+       This enables support for the Apollo display controller in its
+       Hecuba form using the n411 devkit.

This drops the FB_DEFERRED_IO select.. FB_HECUBA has a depends on, but nothing else will select it.

From: Magnus Damm <[email protected]>

Change the metronome driver to use the new shared sys helpers. In the future this driver can setup the "sysdelay" value to delay flushing.

Signed-off-by Magnus Damm <[email protected]>

---

 drivers/video/Kconfig       |    4 -
 drivers/video/metronomefb.c |  102 +++++++------------------------------------
 2 files changed, 17 insertions(+), 89 deletions(-)

drivers/video/Kconfig 2008-12-22 14:07:15.000000000 +0900 renamed from drivers/video/Kconfig +0 -4

@@ -2071,10 +2071,6 @@ config XEN_FBDEV_FRONTEND
 config FB_METRONOME
       tristate "E-Ink Metronome/8track controller support"
       depends on FB
-       select FB_SYS_FILLRECT
-       select FB_SYS_COPYAREA
-       select FB_SYS_IMAGEBLIT
-       select FB_SYS_FOPS
       select FB_DEFERRED_IO
       help
         This driver implements support for the E-Ink Metronome

drivers/video/metronomefb.c 2008-12-22 14:07:15.000000000 +0900 renamed from drivers/video/metronomefb.c +0 -1

@@ -445,7 +445,6 @@ static void metronomefb_dpy_update(struc
 
       cksum = calc_img_cksum((u16 *) par->metromem_img, fbsize/2);
       *((u16 *)(par->metromem_img) + fbsize/2) = cksum;
-       metronome_display_cmd(par);
 }
 
 static u16 metronomefb_dpy_update_page(struct metronomefb_par *par, int index)

@@ -472,97 +471,30 @@ static void metronomefb_dpy_deferred_io(
       struct fb_deferred_io *fbdefio = info->fbdefio;
       struct metronomefb_par *par = info->par;
 

drivers/video/metronomefb.c 2008-12-22 14:07:15.000000000 +0900 renamed from drivers/video/metronomefb.c +9 -73

+       } else {
+               /* walk the written page list and swizzle the data */
+               list_for_each_entry(cur, &fbdefio->pagelist, lru) {
+                       cksum = metronomefb_dpy_update_page(par,
+                                               (cur->index << PAGE_SHIFT));
+                       par->metromem_img_csum -= par->csum_table[cur->index];
+                       par->csum_table[cur->index] = cksum;
+                       par->metromem_img_csum += cksum;
+               }
       }
 
       metronome_display_cmd(par);
 }
 
-static void metronomefb_fillrect(struct fb_info *info,
-                                  const struct fb_fillrect *rect)
-{
-       struct metronomefb_par *par = info->par;
-
-       sys_fillrect(info, rect);
-       metronomefb_dpy_update(par);
-}
-
-static void metronomefb_copyarea(struct fb_info *info,
-                                  const struct fb_copyarea *area)
-{
-       struct metronomefb_par *par = info->par;
-
-       sys_copyarea(info, area);
-       metronomefb_dpy_update(par);
-}
-
-static void metronomefb_imageblit(struct fb_info *info,
-                               const struct fb_image *image)
-{
-       struct metronomefb_par *par = info->par;
-
-       sys_imageblit(info, image);
-       metronomefb_dpy_update(par);
-}
-
-/*
- * this is the slow path from userspace. they can seek and write to
- * the fb. it is based on fb_sys_write
- */
-static ssize_t metronomefb_write(struct fb_info *info, const char __user *buf,
-                               size_t count, loff_t *ppos)
-{
-       struct metronomefb_par *par = info->par;
-       unsigned long p = *ppos;
-       void *dst;
-       int err = 0;
-       unsigned long total_size;
-
-       if (info->state != FBINFO_STATE_RUNNING)
-               return -EPERM;
-
-       total_size = info->fix.smem_len;
-
-       if (p > total_size)
-               return -EFBIG;
-
-       if (count > total_size) {
-               err = -EFBIG;
-               count = total_size;
-       }
-
-       if (count + p > total_size) {
-               if (!err)
-                       err = -ENOSPC;
-
-               count = total_size - p;
-       }
-
-       dst = (void __force *)(info->screen_base + p);
-
-       if (copy_from_user(dst, buf, count))
-               err = -EFAULT;
-
-       if  (!err)
-               *ppos += count;
-
-       metronomefb_dpy_update(par);
-
-       return (err) ? err : count;
-}
-
 static struct fb_ops metronomefb_ops = {
       .owner          = THIS_MODULE,

drivers/video/metronomefb.c static void metronomefb_dpy_deferred_io( · line 476

Quoted 3 lines · Magnus Damm

drivers/video/metronomefb.c +3 -0

+       if (fbdefio->dx != -1) {
+               /* update the entire screen */
+               metronomefb_dpy_update(par);

Okay, overall seems okay. But I'm not confident about this specific change above. The meaning of dx, etc is not clear to me. Okay, I think I found a problem with above. Here's my explanation, please correct me if I'm wrong in my reading of the code you've posted. The typical use case is just a single mmap client (eg: Xfbdev) and nothing else. No fbcon. The only code path I see that sets defio->dx is in the write/blit/* paths via the defio_touch in patch 1/5 and none in the mmap path so with this implementation, all mmap clients would repeatedly only hit the above full update scenario and never use the page based update mechanism.

Other than the above problem, looks okay and its nice to get rid of all that stuff above. :-)

Btw, patch [1/5] is somewhat broken today with the handling of sysdelay vs delay. Ideally I'd like to get rid of sysdelay and let write/blit/* use the same delay as mmap(). Not sure if you are keen on that though since it changes the behavior of your drivers. Otoh that may make fbcon usable on e-paper since it decouples the soft cursor refresh rate from the screen refresh rate.