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. 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 <del...@gmx.de> >> >> 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 >> >
