On Tue, Jan 25, 2022 at 8:44 PM Helge Deller <deller@xxxxxx> wrote: > > On 1/25/22 20:17, Helge Deller wrote: > > On 1/25/22 20:12, Helge Deller wrote: > >> Add a config option CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION to > >> enable bitblt and fillrect hardware acceleration in the framebuffer > >> console. If disabled, such acceleration will not be used, even if it is > >> supported by the graphics hardware driver. > >> > >> If you plan to use DRM as your main graphics output system, you should > >> disable this option since it will prevent compiling in code which isn't > >> used later on when DRM takes over. > >> > >> For all other configurations, e.g. if none of your graphic cards support > >> DRM (yet), DRM isn't available for your architecture, or you can't be > >> sure that the graphic card in the target system will support DRM, you > >> most likely want to enable this option. > >> > >> > >> This patch is the first RFC. > > > > I forgot to mention that by using the static fb_scrollmode() function > > I expect the compiler to optimize-out all code which seems problematic > > from DRM's POV... > > This patch is not complete, for example there are more changes necessary > in fbcon_cw.c, bcon_ccw.c and fbcon_ccw.c. > > Anyway, for the first round I'm interested in general feedback, if this is > the direction which is acceptable for you. > > In addition I think fb_scrollmode() should be renamed to fbcon_scrollmode() > to make it clear that it's a fbcon-related function. I started typing my on flavour of this and wasn't happy with some of the ifdefs, your fb_scrollmode() takes care of the annoying ones in a tidy way. I'll include your diff here and I'll try and get my series sent out today (there's a bunch of random little locking cleanups in fbcon.c that I've done since the code is just a bit too entertaining as-is). Cheers, Daniel > > If you want to test this patch you will need to first apply the revert-patches > I sent earlier. > Alternatively for testing it's possible to pull from the "fbcon-accel" branch from: > https://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git fbcon-accel > > Helge > > > > >> Independed of this patch I did some timing experiments with a qemu > >> virtual machine running a PA-RISC Debian Linux installation with a > >> screen resolution of 2048x1024 with 8bpp. In that case qemu emulated the > >> graphics hardware bitblt and fillrect acceleration by using the native > >> (x86) CPU. > >> > >> It was a simple testcase which was to run "time dmesg", where the syslog > >> had 284 lines. The results showed a huge speedup: > >> a) time dmesg (without acceleration): > >> -> 19.0 seconds > >> b) time dmesg (with acceleration): > >> -> 2.6 seconds > >> > >> Signed-off-by: Helge Deller <deller@xxxxxx> > >> > >> diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig > >> index 840d9813b0bc..da84d1c21c21 100644 > >> --- a/drivers/video/console/Kconfig > >> +++ b/drivers/video/console/Kconfig > >> @@ -78,6 +78,17 @@ config FRAMEBUFFER_CONSOLE > >> help > >> Low-level framebuffer-based console driver. > >> > >> +config FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION > >> + bool "Framebuffer Console hardware acceleration support" > >> + depends on FRAMEBUFFER_CONSOLE > >> + default y if !DRM > >> + default y if !(X86 || ARM) > >> + help > >> + If you use a system on which DRM is fully supported you usually want to say N, > >> + otherwise you probably want to enable this option. > >> + If enabled the framebuffer console will utilize the hardware acceleration > >> + of your graphics card by using hardware bitblt and fillrect features. > >> + > >> config FRAMEBUFFER_CONSOLE_DETECT_PRIMARY > >> bool "Map the console to the primary display device" > >> depends on FRAMEBUFFER_CONSOLE > >> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c > >> index b813985f1403..f7b7d35953e8 100644 > >> --- a/drivers/video/fbdev/core/fbcon.c > >> +++ b/drivers/video/fbdev/core/fbcon.c > >> @@ -1136,11 +1136,13 @@ static void fbcon_init(struct vc_data *vc, int init) > >> > >> ops->graphics = 0; > >> > >> +#ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION > >> if ((cap & FBINFO_HWACCEL_COPYAREA) && > >> !(cap & FBINFO_HWACCEL_DISABLED)) > >> p->scrollmode = SCROLL_MOVE; > >> else /* default to something safe */ > >> p->scrollmode = SCROLL_REDRAW; > >> +#endif > >> > >> /* > >> * ++guenther: console.c:vc_allocate() relies on initializing > >> @@ -1705,7 +1707,7 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b, > >> count = vc->vc_rows; > >> if (logo_shown >= 0) > >> goto redraw_up; > >> - switch (p->scrollmode) { > >> + switch (fb_scrollmode(p)) { > >> case SCROLL_MOVE: > >> fbcon_redraw_blit(vc, info, p, t, b - t - count, > >> count); > >> @@ -1795,7 +1797,7 @@ static bool fbcon_scroll(struct vc_data *vc, unsigned int t, unsigned int b, > >> count = vc->vc_rows; > >> if (logo_shown >= 0) > >> goto redraw_down; > >> - switch (p->scrollmode) { > >> + switch (fb_scrollmode(p)) { > >> case SCROLL_MOVE: > >> fbcon_redraw_blit(vc, info, p, b - 1, b - t - count, > >> -count); > >> @@ -1946,12 +1948,12 @@ static void fbcon_bmove_rec(struct vc_data *vc, struct fbcon_display *p, int sy, > >> height, width); > >> } > >> > >> -static void updatescrollmode(struct fbcon_display *p, > >> +static void updatescrollmode_accel(struct fbcon_display *p, > >> struct fb_info *info, > >> struct vc_data *vc) > >> { > >> +#ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION > >> struct fbcon_ops *ops = info->fbcon_par; > >> - int fh = vc->vc_font.height; > >> int cap = info->flags; > >> u16 t = 0; > >> int ypan = FBCON_SWAP(ops->rotate, info->fix.ypanstep, > >> @@ -1972,12 +1974,6 @@ static void updatescrollmode(struct fbcon_display *p, > >> int fast_imageblit = (cap & FBINFO_HWACCEL_IMAGEBLIT) && > >> !(cap & FBINFO_HWACCEL_DISABLED); > >> > >> - p->vrows = vyres/fh; > >> - if (yres > (fh * (vc->vc_rows + 1))) > >> - p->vrows -= (yres - (fh * vc->vc_rows)) / fh; > >> - if ((yres % fh) && (vyres % fh < yres % fh)) > >> - p->vrows--; > >> - > >> if (good_wrap || good_pan) { > >> if (reading_fast || fast_copyarea) > >> p->scrollmode = good_wrap ? > >> @@ -1991,6 +1987,27 @@ static void updatescrollmode(struct fbcon_display *p, > >> else > >> p->scrollmode = SCROLL_REDRAW; > >> } > >> +#endif > >> +} > >> + > >> +static void updatescrollmode(struct fbcon_display *p, > >> + struct fb_info *info, > >> + struct vc_data *vc) > >> +{ > >> + struct fbcon_ops *ops = info->fbcon_par; > >> + int fh = vc->vc_font.height; > >> + int yres = FBCON_SWAP(ops->rotate, info->var.yres, info->var.xres); > >> + int vyres = FBCON_SWAP(ops->rotate, info->var.yres_virtual, > >> + info->var.xres_virtual); > >> + > >> + p->vrows = vyres/fh; > >> + if (yres > (fh * (vc->vc_rows + 1))) > >> + p->vrows -= (yres - (fh * vc->vc_rows)) / fh; > >> + if ((yres % fh) && (vyres % fh < yres % fh)) > >> + p->vrows--; > >> + > >> + /* update scrollmode in case hardware acceleration is used */ > >> + updatescrollmode_accel(p, info, vc); > >> } > >> > >> #define PITCH(w) (((w) + 7) >> 3) > >> @@ -2148,7 +2165,7 @@ static int fbcon_switch(struct vc_data *vc) > >> > >> updatescrollmode(p, info, vc); > >> > >> - switch (p->scrollmode) { > >> + switch (fb_scrollmode(p)) { > >> case SCROLL_WRAP_MOVE: > >> scrollback_phys_max = p->vrows - vc->vc_rows; > >> break; > >> diff --git a/drivers/video/fbdev/core/fbcon.h b/drivers/video/fbdev/core/fbcon.h > >> index 9315b360c898..c5c043f38162 100644 > >> --- a/drivers/video/fbdev/core/fbcon.h > >> +++ b/drivers/video/fbdev/core/fbcon.h > >> @@ -29,7 +29,9 @@ struct fbcon_display { > >> /* Filled in by the low-level console driver */ > >> const u_char *fontdata; > >> int userfont; /* != 0 if fontdata kmalloc()ed */ > >> +#ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION > >> u_short scrollmode; /* Scroll Method */ > >> +#endif > >> u_short inverse; /* != 0 text black on white as default */ > >> short yscroll; /* Hardware scrolling */ > >> int vrows; /* number of virtual rows */ > >> @@ -208,6 +210,17 @@ static inline int attr_col_ec(int shift, struct vc_data *vc, > >> #define SCROLL_REDRAW 0x004 > >> #define SCROLL_PAN_REDRAW 0x005 > >> > >> +static inline u_short fb_scrollmode(struct fbcon_display *fb) > >> +{ > >> +#ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION > >> + return fb->scrollmode; > >> +#else > >> + /* hardcoded to SCROLL_REDRAW if acceleration was disabled. */ > >> + return SCROLL_REDRAW; > >> +#endif > >> +} > >> + > >> + > >> #ifdef CONFIG_FB_TILEBLITTING > >> extern void fbcon_set_tileops(struct vc_data *vc, struct fb_info *info); > >> #endif > >> > > > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
