Re: [PATCH v3] Fix loading of module radeonfb on PowerMac

From: Mathieu Malaterre
Date: Wed Jan 31 2018 - 14:51:51 EST

Bartlomiej,

On Wed, Jan 31, 2018 at 12:57 PM, Bartlomiej Zolnierkiewicz
<b.zolnierkie@xxxxxxxxxxx> wrote:
> On Tuesday, January 30, 2018 02:14:10 PM Mathieu Malaterre wrote:
>> Bartlomiej,
>>
>> On Wed, Jan 3, 2018 at 3:47 PM, Bartlomiej Zolnierkiewicz
>> <b.zolnierkie@xxxxxxxxxxx> wrote:
>> >
>> > On Thursday, December 21, 2017 11:07:56 PM Mathieu Malaterre wrote:
>> >> When the linux kernel is build with (typical kernel ship with Debian
>> >> installer):
>> >>
>> >> CONFIG_FB_OF=y
>> >> CONFIG_VT_HW_CONSOLE_BINDING=y
>> >> CONFIG_FB_RADEON=m
>> >>
>> >> The offb driver takes precedence over module radeonfb. It is then
>> >> impossible to load the module, error reported is:
>> >>
>> >> [ 96.551486] radeonfb 0000:00:10.0: enabling device (0006 -> 0007)
>> >> [ 96.551526] radeonfb 0000:00:10.0: BAR 0: can't reserve [mem 0x98000000-0x9fffffff pref]
>> >> [ 96.551531] radeonfb (0000:00:10.0): cannot request region 0.
>> >> [ 96.551545] radeonfb: probe of 0000:00:10.0 failed with error -16
>> >>
>> >> This patch reproduce the behavior of the module radeon, so as to make it
>> >> possible to load radeonfb when offb is first loaded.
>> >>
>> >> It should be noticed that `offb_destroy` is never called which explain the
>> >> need to skip error detection on the radeon side.
>> >
>> > This still needs to be explained more, from my last mail:
>> >
>> > "The last put_fb_info() on fb_info should call ->fb_destroy
>> > (offb_destroy in our case) and remove_conflicting_framebuffers()
>> > is calling put_fb_info() so there is some extra reference on
>> > fb_info somewhere preventing it from going away.
>> >
>> > Please look into fixing this."
>>
>> I am not familiar with the fb stuff internals but here is what I see:
>>
>> # modprobe radeonfb
>>
>> leads to:
>>
>> [ 52.058546] bus: 'pci': add driver radeonfb
>> [ 52.058588] bus: 'pci': driver_probe_device: matched device
>> 0000:00:10.0 with driver radeonfb
>> [ 52.058595] bus: 'pci': really_probe: probing driver radeonfb with
>> device 0000:00:10.0
>> [ 52.058608] devices_kset: Moving 0000:00:10.0 to end of list
>> [ 52.058613] radeonfb_pci_register BEGIN
>> [ 52.058634] radeonfb 0000:00:10.0: enabling device (0006 -> 0007)
>> <at this point radeon_kick_out_firmware_fb is called>
>> [ 52.058666] checking generic (9c008000 96000) vs hw (98000000 8000000)
>> [ 52.058667] fb: switching to radeonfb from OFfb ATY,RockHo
>> [ 52.058844] Console: switching to colour dummy device 80x25
>> [ 52.058860] device: 'fb0': device_unregister
>> [ 52.058956] PM: Removing info for No Bus:fb0
>> [ 52.059014] device: 'fb0': device_create_release
>> <a call to do_unregister_framebuffer is done>
>> <put_fb_info is done with a count=2 and dev=NULL>
>> [ 52.059048] device: 'vtcon1': device_unregister
>> [ 52.059076] PM: Removing info for No Bus:vtcon1
>> [ 52.059091] device: 'vtcon1': device_create_release
>> [ 52.059107] radeonfb 0000:00:10.0: BAR 0: can't reserve [mem
>> 0x98000000-0x9fffffff pref]
>> [ 52.256151] aper_base: 98000000 MC_FB_LOC to: 9bff9800, MC_AGP_LOC
>> to: ffffa000
>> [ 52.256157] radeonfb (0000:00:10.0): Found 32768k of DDR 64 bits
>> wide videoram
>>
>> I can confirm that offb_destroy is never called (not sure exactly
>> why), but in any case the call to radeon_kick_out_firmware_fb happen
>> much earlier, at least before the put_fb_info.
>
> It is okay, put_fb_info() is called indirectly by radeon_kick_out_firmware_fb()
>
> radeon_kick_out_firmware_fb()
> remove_conflicting_framebuffers()
> do_remove_conflicting_framebuffers()
> do_unregister_framebuffer()
> put_fb_info()
>
> offb_destroy() is not called because there is an extra reference on old
> fb_info (->count == 2):
>
> static void put_fb_info(struct fb_info *fb_info)
> {
> if (!atomic_dec_and_test(&fb_info->count))
> return;
> if (fb_info->fbops->fb_destroy)
> fb_info->fbops->fb_destroy(fb_info);
> }
>
> The question is why there is an extra reference, probably user-space
> is still holding the fb_info reference obtained in fb_open() call and
> fb_release() is never called. Besides not calling fbops->fb_destroy()
> this also causes missing call of fbops->fb_release() (in fb_release())
> which some fb drivers are implementing (but not offb.c).
>
>> Could you describe a bit more the chain of calls you were thinking of ?
>
> Please add WARN_ON(1) to get_fb_info() and put_fb_info() so we can check
> from the stacktrace if it is actually fb_open() that holds the extra
> old fb_info reference.
>
> drivers/video/fbdev/core/fbmem.c:
>
> static struct fb_info *get_fb_info(unsigned int idx)
> {
> struct fb_info *fb_info;
>
> if (idx >= FB_MAX)
> return ERR_PTR(-ENODEV);
>
> mutex_lock(&registration_lock);
> fb_info = registered_fb[idx];
> if (fb_info)
> atomic_inc(&fb_info->count);
>
> if (fb_info)
> WARN_ON(1);
>
> mutex_unlock(&registration_lock);
>
> return fb_info;
> }
>
> static void put_fb_info(struct fb_info *fb_info)
> {
> WARN_ON(1);
>
> if (!atomic_dec_and_test(&fb_info->count))
> return;
> if (fb_info->fbops->fb_destroy)
> fb_info->fbops->fb_destroy(fb_info);
> }


Alright, here is what I see:

[ 18.961639] PM: Adding info for No Bus:vcs7
[ 18.966448] device: 'vcsa7': device_add
[ 18.966496] PM: Adding info for No Bus:vcsa7
[ 19.001701] WARNING: CPU: 0 PID: 405 at
drivers/video/fbdev/core/fbmem.c:68 get_fb_info.part.3+0x58/0x7c
[ 19.001715] Modules linked in: uinput snd_aoa_codec_toonie
snd_aoa_fabric_layout snd_aoa snd_aoa_i2sbus snd_aoa_soundbus snd_pcm
snd_timer snd soundcore rack_meter evdev i2c_dev sg usb_storage
ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 fscrypto
hid_generic usbhid hid ohci_pci ehci_pci ohci_hcd ehci_hcd sungem
firewire_ohci sungem_phy sr_mod firewire_core crc_itu_t cdrom sd_mod
usbcore
[ 19.001773] CPU: 0 PID: 405 Comm: Xorg Not tainted 4.15.0+ #321
[ 19.001778] NIP: c039ef20 LR: c039eefc CTR: c039ef44
[ 19.001781] REGS: decc7c80 TRAP: 0700 Not tainted (4.15.0+)
[ 19.001784] MSR: 00029032 <EE,ME,IR,DR,RI> CR: 28222828 XER: 00000000
[ 19.001795]
GPR00: c039eefc decc7d30 c147ab00 00000000 dc3ed8c0
df568a6c 00000001 c147ab00
GPR08: df568a6c 00000002 00000000 dc280c50 28222822
006f9ff4 006fff50 80000000
GPR16: 88000228 00000008 bfcb5b08 00000002 decc7e60
80000000 ffffffea 00000041
GPR24: 00000000 00000006 df568a6c dc3ed8c0 df5ef1e8
df568a40 c08f7c18 dc198800
[ 19.001835] NIP [c039ef20] get_fb_info.part.3+0x58/0x7c
[ 19.001840] LR [c039eefc] get_fb_info.part.3+0x34/0x7c
[ 19.001842] Call Trace:
[ 19.001848] [decc7d30] [c039eefc] get_fb_info.part.3+0x34/0x7c (unreliable)
[ 19.001854] [decc7d40] [c039efa0] fb_open+0x5c/0x18c
[ 19.001866] [decc7d60] [c01e0e90] chrdev_open+0xb8/0x19c
[ 19.001872] [decc7d90] [c01d7994] do_dentry_open+0x24c/0x398
[ 19.001881] [decc7dc0] [c01ec378] path_openat+0x4c4/0x11b8
[ 19.001888] [decc7e50] [c01ee0d8] do_filp_open+0xbc/0x10c
[ 19.001893] [decc7f00] [c01d93b0] do_sys_open+0x158/0x228
[ 19.001901] [decc7f40] [c00181cc] ret_from_syscall+0x0/0x40
[ 19.001908] --- interrupt: c01 at 0xb751b940
LR = 0xb751b8dc
[ 19.001912] Instruction dump:
[ 19.001917] 7fc3f378 57ff103a 482cc171 3d20c093 39291a84 7fe9f82e
2f9f0000 419e0018
[ 19.001927] 7d20f828 31290001 7d20f92d 40a2fff4 <0fe00000> 7fc3f378
482cca69 7fe3fb78
[ 19.001938] ---[ end trace e0bf4192eb1c4f60 ]---
[ 19.001985] WARNING: CPU: 0 PID: 405 at
drivers/video/fbdev/core/fbmem.c:77 put_fb_info+0x18/0x68
[ 19.001988] Modules linked in: uinput snd_aoa_codec_toonie
snd_aoa_fabric_layout snd_aoa snd_aoa_i2sbus snd_aoa_soundbus snd_pcm
snd_timer snd soundcore rack_meter evdev i2c_dev sg usb_storage
ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 fscrypto
hid_generic usbhid hid ohci_pci ehci_pci ohci_hcd ehci_hcd sungem
firewire_ohci sungem_phy sr_mod firewire_core crc_itu_t cdrom sd_mod
usbcore
[ 19.002028] CPU: 0 PID: 405 Comm: Xorg Tainted: G W
4.15.0+ #321
[ 19.002031] NIP: c039e6ec LR: c039eeb0 CTR: c039ee48
[ 19.002035] REGS: decc7e10 TRAP: 0700 Tainted: G W (4.15.0+)
[ 19.002037] MSR: 00029032 <EE,ME,IR,DR,RI> CR: 28000222 XER: 20000000
[ 19.002047]
GPR00: c039eeb0 decc7ec0 c147ab00 dc198800 dc3ed8c0
dc3ed8c8 00000001 c147ab00
GPR08: 00000000 c08fa6f8 00000000 dc280c50 28000228
006f9ff4 006fff50 00000000
GPR16: 007001a8 00000008 bfcb5b08 007001a4 00000000
0070d0c4 00000002 00000000
GPR24: b6ad8b1c dc3ed8c8 df5ef1e8 df3e4ee0 dc280c50
df5ef1e8 dc19880c dc198800
[ 19.002086] NIP [c039e6ec] put_fb_info+0x18/0x68
[ 19.002091] LR [c039eeb0] fb_release+0x68/0x80
[ 19.002093] Call Trace:
[ 19.002096] [decc7ec0] [df5ef1e8] 0xdf5ef1e8 (unreliable)
[ 19.002102] [decc7ed0] [c039eeb0] fb_release+0x68/0x80
[ 19.002108] [decc7ee0] [c01dd2e8] __fput+0xb4/0x260
[ 19.002118] [decc7f10] [c006e088] task_work_run+0xc0/0xe8
[ 19.002129] [decc7f30] [c000aa90] do_notify_resume+0xb4/0xb8
[ 19.002135] [decc7f40] [c0018b4c] do_user_signal+0x7c/0xcc
[ 19.002140] --- interrupt: c00 at 0xb751a7d8
LR = 0xb751a7ac
[ 19.002144] Instruction dump:
[ 19.002147] 80010014 38210010 7c0803a6 4e800020 38600000 4e800020
7c0802a6 90010004
[ 19.002157] 60000000 9421fff0 7c0802a6 90010014 <0fe00000> 7d401828
314affff 7d40192d
[ 19.002168] ---[ end trace e0bf4192eb1c4f61 ]---
[ 19.002595] WARNING: CPU: 0 PID: 405 at
drivers/video/fbdev/core/fbmem.c:68 get_fb_info.part.3+0x58/0x7c
[ 19.002601] Modules linked in: uinput snd_aoa_codec_toonie
snd_aoa_fabric_layout snd_aoa snd_aoa_i2sbus snd_aoa_soundbus snd_pcm
snd_timer snd soundcore rack_meter evdev i2c_dev sg usb_storage
ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 fscrypto
hid_generic usbhid hid ohci_pci ehci_pci ohci_hcd ehci_hcd sungem
firewire_ohci sungem_phy sr_mod firewire_core crc_itu_t cdrom sd_mod
usbcore
[ 19.002645] CPU: 0 PID: 405 Comm: Xorg Tainted: G W
4.15.0+ #321
[ 19.002649] NIP: c039ef20 LR: c039eefc CTR: c039ef44
[ 19.002652] REGS: decc7c80 TRAP: 0700 Tainted: G W (4.15.0+)
[ 19.002655] MSR: 00029032 <EE,ME,IR,DR,RI> CR: 28222248 XER: 00000000
[ 19.002664]
GPR00: c039eefc decc7d30 c147ab00 00000000 deca0340
deca0348 00000001 00000000
GPR08: 00000000 00000002 00000000 dc280c50 28222842
006f9ff4 006fff50 80000000
GPR16: 88000448 00000001 00000000 00000002 decc7e60
80000000 ffffffea 00000041
GPR24: 00000000 00000006 c01e0dd8 deca0340 df5ef1e8
df568a40 c08f7c18 dc198800
[ 19.002704] NIP [c039ef20] get_fb_info.part.3+0x58/0x7c
[ 19.002708] LR [c039eefc] get_fb_info.part.3+0x34/0x7c
[ 19.002711] Call Trace:
[ 19.002716] [decc7d30] [c039eefc] get_fb_info.part.3+0x34/0x7c (unreliable)
[ 19.002722] [decc7d40] [c039efa0] fb_open+0x5c/0x18c
[ 19.002730] [decc7d60] [c01e0e90] chrdev_open+0xb8/0x19c
[ 19.002735] [decc7d90] [c01d7994] do_dentry_open+0x24c/0x398
[ 19.002743] [decc7dc0] [c01ec378] path_openat+0x4c4/0x11b8
[ 19.002748] [decc7e50] [c01ee0d8] do_filp_open+0xbc/0x10c
[ 19.002754] [decc7f00] [c01d93b0] do_sys_open+0x158/0x228
[ 19.002760] [decc7f40] [c00181cc] ret_from_syscall+0x0/0x40
[ 19.002766] --- interrupt: c01 at 0xb751b940
LR = 0xb751b8dc
[ 19.002770] Instruction dump:
[ 19.002774] 7fc3f378 57ff103a 482cc171 3d20c093 39291a84 7fe9f82e
2f9f0000 419e0018
[ 19.002784] 7d20f828 31290001 7d20f92d 40a2fff4 <0fe00000> 7fc3f378
482cca69 7fe3fb78
[ 19.002795] ---[ end trace e0bf4192eb1c4f62 ]---
[ 19.011629] gem 0002:20:0f.0 eth0: Link is up at 100 Mbps, full-duplex
[ 19.011746] gem 0002:20:0f.0 eth0: Pause is disabled
[ 19.011846] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 19.018954] device: 'input3': device_add
[ 19.019031] PM: Adding info for No Bus:input3


Then later on (after modprobe radeonfb):

[ 657.135105] PM: Removing info for No Bus:fb0
[ 657.135164] device: 'fb0': device_create_release
[ 657.135279] WARNING: CPU: 0 PID: 475 at
drivers/video/fbdev/core/fbmem.c:77 put_fb_info+0x18/0x68
[ 657.135284] Modules linked in: radeonfb(+) uinput
snd_aoa_codec_toonie snd_aoa_fabric_layout snd_aoa snd_aoa_i2sbus
snd_aoa_soundbus snd_pcm snd_timer snd soundcore rack_meter evdev
i2c_dev sg usb_storage ip_tables x_tables autofs4 ext4 crc16 mbcache
jbd2 fscrypto hid_generic usbhid hid ohci_pci ehci_pci ohci_hcd
ehci_hcd sungem firewire_ohci sungem_phy sr_mod firewire_core
crc_itu_t cdrom sd_mod usbcore
[ 657.135344] CPU: 0 PID: 475 Comm: modprobe Tainted: G W
4.15.0+ #321
[ 657.135348] NIP: c039e6ec LR: c039e834 CTR: 00000000
[ 657.135352] REGS: dec93af0 TRAP: 0700 Tainted: G W (4.15.0+)
[ 657.135355] MSR: 00029032 <EE,ME,IR,DR,RI> CR: 24228822 XER: 20000000
[ 657.135365]
GPR00: c039e834 dec93ba0 dc28eaa0 dc198800 00000000
000005c0 00000002 00000000
GPR08: 00001032 c08c2c2c 00000000 c08c1ab0 28228424
0049ce6c e2287b5c 00000000
GPR16: c06974dc 00000007 e2284384 00000001 dec9852c
e2282610 00000000 000a0000
GPR24: c07c9d60 c07c9d2c dc19880c 00000000 dec93bb8
00000000 c0931a84 dc198800
[ 657.135405] NIP [c039e6ec] put_fb_info+0x18/0x68
[ 657.135411] LR [c039e834] do_unregister_framebuffer+0xf8/0x148
[ 657.135413] Call Trace:
[ 657.135419] [dec93bb0] [c039e834] do_unregister_framebuffer+0xf8/0x148
[ 657.135425] [dec93be0] [c039ea1c]
do_remove_conflicting_framebuffers+0x198/0x1b8
[ 657.135431] [dec93c30] [c039ea84] remove_conflicting_framebuffers+0x48/0x6c
[ 657.135474] [dec93c50] [e2274d6c]
radeonfb_pci_register+0x184/0x1838 [radeonfb]
[ 657.135481] [dec93cb0] [c037e9fc] pci_device_probe+0x110/0x180
[ 657.135492] [dec93ce0] [c045be70] driver_probe_device+0x378/0x4a0
[ 657.135497] [dec93d10] [c045c0ac] __driver_attach+0x114/0x118
[ 657.135503] [dec93d30] [c04593dc] bus_for_each_dev+0x74/0xc0
[ 657.135508] [dec93d60] [c045acd4] bus_add_driver+0x18c/0x2a0
[ 657.135515] [dec93d80] [c045ce3c] driver_register+0x94/0x13c
[ 657.135524] [dec93d90] [c0004af4] do_one_initcall+0x4c/0x178
[ 657.135536] [dec93df0] [c00ced18] do_init_module+0x70/0x1ec
[ 657.135542] [dec93e10] [c00cdcb0] load_module+0x20d8/0x26b8
[ 657.135548] [dec93ec0] [c00ce500] SyS_finit_module+0xc4/0x120
[ 657.135555] [dec93f40] [c00181cc] ret_from_syscall+0x0/0x40
[ 657.135562] --- interrupt: c01 at 0x34d450
LR = 0x476108
[ 657.135566] Instruction dump:
[ 657.135572] 80010014 38210010 7c0803a6 4e800020 38600000 4e800020
7c0802a6 90010004
[ 657.135582] 60000000 9421fff0 7c0802a6 90010014 <0fe00000> 7d401828
314affff 7d40192d
[ 657.135593] ---[ end trace e0bf4192eb1c4f63 ]---
[ 657.135613] device: 'vtcon1': device_unregister
[ 657.135644] PM: Removing info for No Bus:vtcon1


Full dmesg:
https://people.debian.org/~malat/dmesg_radeonfb.txt

Does that help at all? the call stack does not make much sense to me.
I am accessing the Mac Mini over ssh.

For reference, the patch I used is:
https://github.com/malaterre/linux/commit/89fd7d4438c5200a1a4fcba1d60dd701fda4f40e.patch


>> >> Signed-off-by: Mathieu Malaterre <malat@xxxxxxxxxx>
>> >> Link: https://bugs.debian.org/826629#57
>> >> Link: https://bugzilla.kernel.org/show_bug.cgi?id=119741
>> >> Suggested-by: Lennart Sorensen <lsorense@xxxxxxxxxxxxxxxxxxx>
>> >> ---
>> >> v2: Only fails when CONFIG_PCC is not set
>> >> v3: Only fails when CONFIG_FB_OF is not set, CONFIG_PCC was too broad. Since the conflicts in region is due to OFfb explicitly refers to it.
>> >
>> > It seems that there may still be configurations when this is
>> > incorrect -> when offb drives primary (non-radeon) card and radeonfb
>> > drives secondary (radeon) card..
>> >
>> >> drivers/video/fbdev/aty/radeon_base.c | 26 ++++++++++++++++++++++++++
>> >> 1 file changed, 26 insertions(+)
>> >>
>> >> diff --git a/drivers/video/fbdev/aty/radeon_base.c b/drivers/video/fbdev/aty/radeon_base.c
>> >> index 4d77daeecf99..221879196531 100644
>> >> --- a/drivers/video/fbdev/aty/radeon_base.c
>> >> +++ b/drivers/video/fbdev/aty/radeon_base.c
>> >> @@ -2259,6 +2259,22 @@ static const struct bin_attribute edid2_attr = {
>> >> .read = radeon_show_edid2,
>> >> };
>> >>
>> >> +static int radeon_kick_out_firmware_fb(struct pci_dev *pdev)
>> >> +{
>> >> + struct apertures_struct *ap;
>> >> +
>> >> + ap = alloc_apertures(1);
>> >> + if (!ap)
>> >> + return -ENOMEM;
>> >> +
>> >> + ap->ranges[0].base = pci_resource_start(pdev, 0);
>> >> + ap->ranges[0].size = pci_resource_len(pdev, 0);
>> >> +
>> >> + remove_conflicting_framebuffers(ap, KBUILD_MODNAME, false);
>> >> + kfree(ap);
>> >> +
>> >> + return 0;
>> >> +}
>> >>
>> >> static int radeonfb_pci_register(struct pci_dev *pdev,
>> >> const struct pci_device_id *ent)
>> >> @@ -2312,19 +2328,27 @@ static int radeonfb_pci_register(struct pci_dev *pdev,
>> >> rinfo->fb_base_phys = pci_resource_start (pdev, 0);
>> >> rinfo->mmio_base_phys = pci_resource_start (pdev, 2);
>> >>
>> >> + ret = radeon_kick_out_firmware_fb(pdev);
>> >> + if (ret)
>> >> + return ret;
>> >> +
>> >> /* request the mem regions */
>> >> ret = pci_request_region(pdev, 0, "radeonfb framebuffer");
>> >> if (ret < 0) {
>> >> +#ifndef CONFIG_FB_OF
>> >> printk( KERN_ERR "radeonfb (%s): cannot request region 0.\n",
>> >> pci_name(rinfo->pdev));
>> >> goto err_release_fb;
>> >> +#endif
>> >> }
>> >>
>> >> ret = pci_request_region(pdev, 2, "radeonfb mmio");
>> >> if (ret < 0) {
>> >> +#ifndef CONFIG_FB_OF
>> >> printk( KERN_ERR "radeonfb (%s): cannot request region 2.\n",
>> >> pci_name(rinfo->pdev));
>> >> goto err_release_pci0;
>> >> +#endif
>> >> }
>> >>
>> >> /* map the regions */
>> >> @@ -2509,10 +2533,12 @@ static int radeonfb_pci_register(struct pci_dev *pdev,
>> >> iounmap(rinfo->mmio_base);
>> >> err_release_pci2:
>> >> pci_release_region(pdev, 2);
>> >> +#ifndef CONFIG_FB_OF
>> >> err_release_pci0:
>> >> pci_release_region(pdev, 0);
>> >> err_release_fb:
>> >> framebuffer_release(info);
>> >> +#endif
>> >> err_disable:
>> >> err_out:
>> >> return ret;
>> >
>> > Best regards,
>> > --
>> > Bartlomiej Zolnierkiewicz
>> > Samsung R&D Institute Poland
>> > Samsung Electronics
>> >
>>
>> Thanks,
>> -M
>
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics

Thanks much !