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linux/drivers/video/fbdev
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Dave Airlie dd0c41f8a7 efifb: allow user to disable write combined mapping. 
This patch allows the user to disable write combined mapping
of the efifb framebuffer console using an nowc option.

A customer noticed major slowdowns while logging to the console
with write combining enabled, on other tasks running on the same
CPU. (10x or greater slow down on all other cores on the same CPU
as is doing the logging).

I reproduced this on a machine with dual CPUs.
Intel(R) Xeon(R) CPU E5-2609 v3 @ 1.90GHz (6 core)

I wrote a test that just mmaps the pci bar and writes to it in
a loop, while this was running in the background one a single
core with (taskset -c 1), building a kernel up to init/version.o
(taskset -c 8) went from 13s to 133s or so. I've yet to explain
why this occurs or what is going wrong I haven't managed to find
a perf command that in any way gives insight into this.

    11,885,070,715      instructions              #    1.39  insns per cycle
vs
    12,082,592,342      instructions              #    0.13  insns per cycle

is the only thing I've spotted of interest, I've tried at least:
dTLB-stores,dTLB-store-misses,L1-dcache-stores,LLC-store,LLC-store-misses,LLC-load-misses,LLC-loads,\mem-loads,mem-stores,iTLB-loads,iTLB-load-misses,cache-references,cache-misses

For now it seems at least a good idea to allow a user to disable write
combining if they see this until we can figure it out.

Note also most users get a real framebuffer driver loaded when kms
kicks in, it just happens on these machines the kernel didn't support
the gpu specific driver.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Acked-by: Peter Jones <pjones@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
 		2017-07-31 18:45:41 +02:00
..
aty atyfb: hide unused variable 2017-07-12 18:28:10 +02:00
core fbdev changes for v4.13: 2017-07-13 11:52:00 -07:00
geode video: constify geode ops structures 2015-12-15 15:41:22 +02:00
i810 video: fbdev: i810: remove incorrect __exit markups 2017-03-20 18:31:00 +01:00
intelfb video: fbdev: intelfb: move inline before return type 2017-07-12 16:26:04 -07:00
kyro video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
matrox video: fbdev: matrox: the list iterator can't be NULL 2017-07-04 17:47:23 +02:00
mb862xx video: fbdev: mb862xx: remove unused variable 2016-08-30 12:00:15 +03:00
mbx video/mbx: use simple_open() 2017-01-30 17:39:49 +01:00
mmp fbdev: mmp: print IRQ resource using %pR format string 2016-01-29 13:42:58 +02:00
nvidia sched/headers: Prepare for new header dependencies before moving code to <linux/sched/nmi.h> 2017-03-02 08:42:30 +01:00
omap Merge branch 'akpm' (patches from Andrew) 2017-07-13 12:38:49 -07:00
omap2 fbdev: omapfb: remove unused variable 2017-07-31 18:45:41 +02:00
riva video: fbdev: rivafb: unlock chip before probiding EDID 2015-12-15 15:41:23 +02:00
savage video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
sis video: fbdev: sis: remove unused variable 2016-03-03 13:38:29 +02:00
vermilion vmlfb: Fix error handling in cr_pll_init() 2017-07-04 17:47:23 +02:00
via video: fbdev: via: remove possibly unused variables 2017-06-14 12:40:36 +02:00
68328fb.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
Kconfig fbdev: sti: don't select CONFIG_VT 2017-05-05 17:25:12 +02:00
Makefile video: fbdev: exynos: Remove old non-working MIPI driver 2016-09-27 11:05:29 +03:00
acornfb.c drivers/video/fbdev: Fixing coding guidelines in acornfb.c 2017-04-07 17:03:24 +02:00
acornfb.h
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amba-clcd-nomadik.c fbdev changes for v4.11: 2017-02-25 13:20:22 -08:00
amba-clcd-nomadik.h video: ARM CLCD: use panel device node for panel initialization 2017-01-30 17:39:48 +01:00
amba-clcd-versatile.c video: ARM CLCD: use panel device node for panel initialization 2017-01-30 17:39:48 +01:00
amba-clcd-versatile.h video: ARM CLCD: use panel device node for panel initialization 2017-01-30 17:39:48 +01:00
amba-clcd.c video: ARM CLCD: fix dma allocation size 2017-04-07 17:03:24 +02:00
amifb.c video: fbdev: amifb: remove impossible condition 2017-02-08 16:44:00 +01:00
arcfb.c Annotate hardware config module parameters in drivers/video/ 2017-04-20 12:02:32 +01:00
arkfb.c drivers/video/fbdev/arkfb.c: Use arch_phys_wc_add() and pci_iomap_wc() 2015-08-25 09:59:45 +02:00
asiliantfb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
atafb.c fbdev: kill fb_rotate 2016-02-26 13:28:35 +02:00
atafb.h
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atafb_iplan2p2.c
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atafb_iplan2p4.c
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atafb_iplan2p8.c
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atafb_mfb.c
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atafb_utils.h
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atmel_lcdfb.c This is the bulk of GPIO changes for kernel v4.6: 2016-03-17 21:05:32 -07:00
au1100fb.c au1100fb: remove a bogus dma_free_nonconsistent call 2017-06-28 06:54:57 -07:00
au1100fb.h MIPS: Alchemy: au1100fb: use clk framework 2014-07-30 14:10:39 +02:00
au1200fb.c dma-mapping: replace dmam_alloc_noncoherent with dmam_alloc_attrs 2017-06-28 06:55:00 -07:00
au1200fb.h
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auo_k190x.c sched/headers: Remove the <linux/mm_types.h> dependency from <linux/sched.h> 2017-03-03 01:45:16 +01:00
auo_k190x.h
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auo_k1900fb.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
auo_k1901fb.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
bf54x-lq043fb.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
bf537-lq035.c fbdev: kill fb_rotate 2016-02-26 13:28:35 +02:00
bfin-lq035q1-fb.c
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bfin-t350mcqb-fb.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
bfin_adv7393fb.c fb: adv7393: off by one in probe function 2016-08-30 12:06:12 +03:00
bfin_adv7393fb.h fbdev/bfin_adv7393fb: move DRIVER_NAME before its first use 2016-08-02 19:35:05 -04:00
broadsheetfb.c fbdev: broadsheetfb: fix memory leak 2015-09-30 10:33:57 +03:00
bt431.h video: fbdev: bt431: Correct cursor format control macro 2016-02-26 13:06:11 +02:00
bt455.h video: fbdev: pmag-ba-fb: Optimize Bt455 colormap addressing 2016-02-26 13:06:11 +02:00
bw2.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
c2p.h
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c2p_core.h
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c2p_iplan2.c
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c2p_planar.c
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carminefb.c
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carminefb.h
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carminefb_regs.h
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cg3.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
cg6.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
cg14.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
chipsfb.c fbdev: Remove __init from chips_hw_init() to fix build failure 2014-08-26 12:48:34 +03:00
cirrusfb.c
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clps711x-fb.c video: clps711x-fb: Changing the compatibility string to match with the smallest supported chip 2016-07-06 17:38:19 +02:00
clps711xfb.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
cobalt_lcdfb.c sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h> 2017-03-02 08:42:32 +01:00
controlfb.c powerpc: Move Power Macintosh drivers to generic byteswappers 2015-03-23 14:29:40 +11:00
controlfb.h
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cyber2000fb.c video: fbdev: cyber2000fb.c: use container_of to resolve cfb_info from fb_info 2014-09-30 13:06:01 +03:00
cyber2000fb.h
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da8xx-fb.c remove lots of IS_ERR_VALUE abuses 2016-05-27 15:26:11 -07:00
dnfb.c
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edid.h
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efifb.c efifb: allow user to disable write combined mapping. 2017-07-31 18:45:41 +02:00
ep93xx-fb.c dma, mm/pat: Rename dma_*_writecombine() to dma_*_wc() 2016-03-09 14:57:51 +01:00
fb-puv3.c drivers/video/fbdev/fb-puv3.c: Add header files for function unifb_mmap 2014-05-23 13:51:10 +03:00
ffb.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
fm2fb.c
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fsl-diu-fb.c video: fbdev: fsl-diu-fb: constify mfb_template and fsl_diu_match. 2017-07-04 17:47:22 +02:00
g364fb.c
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gbefb.c dma, mm/pat: Rename dma_*_writecombine() to dma_*_wc() 2016-03-09 14:57:51 +01:00
goldfishfb.c
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grvga.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
gxt4500.c gxt4500: enable panning 2015-10-08 12:19:39 +03:00
hecubafb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
hgafb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
hitfb.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
hpfb.c hpfb: use probe_kernel_read() 2017-05-27 15:41:17 -04:00
hyperv_fb.c drivers:hv: Use new vmbus_mmio_free() from client drivers. 2016-04-30 14:01:37 -07:00
i740_reg.h
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i740fb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
igafb.c
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imsttfb.c PCI: Remove includes of asm/pci-bridge.h 2016-02-05 16:29:28 -06:00
imxfb.c video: fbdev: imxfb: use after free in imxfb_remove() 2017-07-31 18:45:41 +02:00
jz4740_fb.c fbdev: jz4740-fb: Let the pinctrl driver configure the pins 2017-05-22 17:22:06 +02:00
leo.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
macfb.c
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macmodes.c
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macmodes.h
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maxinefb.c video: fbdev: maxinefb: add __initdata to maxinefb_fix 2017-01-11 17:09:50 +01:00
metronomefb.c lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
mx3fb.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
mxsfb.c video: mxsfb: Fix framebuffer corruption on mx6sx 2016-08-30 11:59:33 +03:00
n411.c Annotate hardware config module parameters in drivers/video/ 2017-04-20 12:02:32 +01:00
neofb.c video: fbdev: neofb: use arch_phys_wc_add() and ioremap_wc() 2015-06-03 12:41:49 +03:00
nuc900fb.c dma, mm/pat: Rename dma_*_writecombine() to dma_*_wc() 2016-03-09 14:57:51 +01:00
nuc900fb.h
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ocfb.c ocfb: fix tgdel and tvdel timing parameters 2016-01-29 13:34:07 +02:00
offb.c video: fbdev: offb: switch to using for_each_node_by_type 2017-02-08 16:43:59 +01:00
p9100.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
platinumfb.c powerpc: Move Power Macintosh drivers to generic byteswappers 2015-03-23 14:29:40 +11:00
platinumfb.h
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pm2fb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
pm3fb.c video: fbdev: pm3fb: use arch_phys_wc_add() and ioremap_wc() 2015-06-03 12:41:52 +03:00
pmag-aa-fb.c video: fbdev: pmag-aa-fb: remove incorrect __exit markups 2017-03-20 18:31:00 +01:00
pmag-ba-fb.c video: fbdev: pmag-ba-fb: remove incorrect __exit markups 2017-03-20 18:30:59 +01:00
pmagb-b-fb.c video: fbdev: pmagb-b-fb: remove incorrect __exit markups 2017-03-20 18:31:00 +01:00
ps3fb.c
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pvr2fb.c mm: replace get_user_pages_unlocked() write/force parameters with gup_flags 2016-10-18 14:13:37 -07:00
pxa3xx-gcu.c video: fbdev: pxa3xx_gcu: prepare the clocks 2015-08-10 12:25:43 +03:00
pxa3xx-gcu.h
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pxa168fb.c dma, mm/pat: Rename dma_*_writecombine() to dma_*_wc() 2016-03-09 14:57:51 +01:00
pxa168fb.h
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pxafb.c video: fbdev: pxafb: Handle return value of clk_prepare_enable 2017-06-14 17:40:56 +02:00
pxafb.h video: fbdev: pxafb: loosen the platform data bond 2015-12-15 15:41:24 +02:00
q40fb.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
s1d13xxxfb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
s3c-fb.c dma, mm/pat: Rename dma_*_writecombine() to dma_*_wc() 2016-03-09 14:57:51 +01:00
s3c2410fb.c video: s3c2410fb: Register cpufreq notifier only on S3C24xx 2016-08-11 17:54:55 +03:00
s3c2410fb.h video: s3c2410fb: Register cpufreq notifier only on S3C24xx 2016-08-11 17:54:55 +03:00
s3fb.c drivers/video/fbdev/s3fb: Use arch_phys_wc_add() and pci_iomap_wc() 2015-08-25 09:59:45 +02:00
sa1100fb.c dma, mm/pat: Rename dma_*_writecombine() to dma_*_wc() 2016-03-09 14:57:51 +01:00
sa1100fb.h ARM: 8244/1: fbdev: sa1100fb: make use of device clock 2014-12-05 16:30:25 +00:00
sbuslib.c
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sbuslib.h
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sh7760fb.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
sh_mobile_lcdcfb.c video: fbdev: sh_mobile_lcdcfb: constify sh_mobile_lcdc_bl_ops. 2017-06-14 17:40:57 +02:00
sh_mobile_lcdcfb.h
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sh_mobile_meram.c More ACPI and power management updates for 3.19-rc1 2014-12-18 20:28:33 -08:00
simplefb.c video: fbdev: simplefb: Separate clk / regulator get and enable steps 2017-01-11 17:09:50 +01:00
skeletonfb.c docs: fix locations of several documents that got moved 2016-10-24 08:12:35 -02:00
sm501fb.c sm501fb: don't return zero on failure path in sm501fb_start() 2017-05-02 13:47:53 +02:00
sm712.h staging: sm7xxfb: merge sm712fb with fbdev 2015-08-07 15:05:01 -07:00
sm712fb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
smscufx.c video: fbdev: add missing USB-descriptor endianness conversions 2017-06-14 12:40:36 +02:00
ssd1307fb.c fbdev/ssd1307fb: fix optional VBAT support 2017-04-07 17:28:23 +02:00
sstfb.c
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sticore.h
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stifb.c video: fbdev: stifb: handle NULL return value from ioremap_nocache 2017-01-30 17:39:49 +01:00
sunxvr500.c drivers/video: make fbdev/sunxvr500.c explicitly non-modular 2016-03-03 13:36:51 +02:00
sunxvr1000.c drivers/video: make fbdev/sunxvr1000.c explicitly non-modular 2016-03-03 13:36:51 +02:00
sunxvr2500.c drivers/video: make fbdev/sunxvr2500.c explicitly non-modular 2016-03-03 13:36:51 +02:00
tcx.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
tdfxfb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
tgafb.c
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tmiofb.c
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tridentfb.c fbdev changes for 4.4 2015-11-10 10:00:09 -08:00
udlfb.c video: fbdev: udlfb: drop log level for blanking 2017-06-14 12:40:36 +02:00
uvesafb.c uvesafb: Fix continuation printks without KERN_LEVEL to pr_cont, neatening 2017-06-14 17:40:57 +02:00
valkyriefb.c video: fbdev: valkyriefb.c: use container_of to resolve fb_info_valkyrie from fb_info 2014-09-30 13:06:01 +03:00
valkyriefb.h
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vesafb.c video: fbdev: vesafb: use arch_phys_wc_add() 2015-06-16 09:42:11 +03:00
vfb.c fbdev: vfb: simplify memory management 2016-09-07 12:06:53 +03:00
vga16fb.c video: fbdev: constify fb_fix_screeninfo and fb_var_screeninfo structures 2016-09-27 11:16:35 +03:00
vt8500lcdfb.c video: vt8500lcdfb: remove unneeded continue 2015-01-13 13:35:04 +02:00
vt8500lcdfb.h
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vt8623fb.c drivers/video/fbdev/vt8623fb: Use arch_phys_wc_add() and pci_iomap_wc() 2015-08-25 09:59:45 +02:00
w100fb.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
w100fb.h
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wm8505fb.c video: fbdev: wm8505fb use permission-specific DEVICE_ATTR variants 2017-01-11 17:09:51 +01:00
wm8505fb_regs.h
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wmt_ge_rops.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00
wmt_ge_rops.h
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xen-fbfront.c fbdev changes for v4.12: 2017-05-11 11:12:26 -07:00
xilinxfb.c video: fbdev: drop owner assignment from platform_drivers 2014-10-20 16:21:51 +02:00