cx88-dvb: Fix Oops in case i2c bus failed to register

PATCH Darron Broad 1 participant 1 message Oct 24, 2008 1 message not in the archive Media (V4L/DVB)

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A message that is not in the archive (sent off-list or not yet received): [email protected]

Darron Broad

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2008-10-24 15:25 UTC #1 lore raw

In message <[email protected]>, Matthias Schwarzott wrote:

Hiya.

Quoted 13 lines

Hi!
@Mauro: Please pull this patch
There already is an report at kernel bugzilla about this issue:
http://bugzilla.kernel.org/show_bug.cgi?id=9455
When enabling extra checks for the i2c-bus of cx88 based cards by loading i2c_algo_bit with bit_test=1 this may trigger an oops when loading cx88_dvb.
This is caused by the extra check code that detects that the sda-line is stuck high and thus does not register the i2c-bus.

Quoted 6 lines

cx88-dvb however does not check if the i2c-bus is valid and just uses core->i2c_adap to attach dvb frontend modules. This leads to an oops at the first call to i2c_transfer:
# modprobe i2c_algo_bit bit_test=1
# modprobe cx8802

Thanks for this information. If you don't mind, would you let me utilise this fix in another way?

I have been auditing MFE additions and I need to change something elsewhere and can see an alternative to to bailing out in dvb_register?

Thanks

Quoted 124 lines

cx88/2: cx2388x MPEG-TS Driver Manager version 0.0.6 loaded cx88[0]: quirk: PCIPCI_NATOMA -- set TBFX
cx88[0]: subsystem: 0070:9202, board: Hauppauge Nova-S-Plus DVB-S [card=37,autodetected], frontend(s): 1
cx88[0]: TV tuner type 4, Radio tuner type -1
cx88[0]: SDA stuck high!
cx88[0]: i2c register FAILED
input: cx88 IR (Hauppauge Nova-S-Plus as /class/input/input5 cx88[0]/2: cx2388x 8802 Driver Manager
cx88-mpeg driver manager 0000:00:10.2: enabling device (0154 -> 0156) cx88-mpeg driver manager 0000:00:10.2: PCI INT A -> Link[LNKD] -> GSI 9 (level, low) -> IRQ 9
cx88[0]/2: found at 0000:00:10.2, rev: 5, irq: 9, latency: 64, mmio:
0xfb000000
cx8802_probe() allocating 1 frontend(s)
cx88/2: cx2388x dvb driver version 0.0.6 loaded
cx88/2: registering cx8802 driver, type: dvb access: shared cx88[0]/2: subsystem: 0070:9202, board: Hauppauge Nova-S-Plus DVB-S [card=37] cx88[0]/2: cx2388x based DVB/ATSC card
BUG: unable to handle kernel NULL pointer dereference at 00000000
IP: [<e084d4ef>] :i2c_core:i2c_transfer+0x1f/0x80
*pde = 00000000
Modules linked in: cx88_dvb(+) cx8802 cx88xx ir_common i2c_algo_bit tveeprom 
videobuf_dvb btcx_risc
mga drm ipv6 fscpos eeprom nfsd exportfs stv0299 b2c2_flexcop_pci b2c2_flexcop cx24123 s5h1420 ves1x93
dvb_ttpci dvb_core saa7146_vv saa7146 videobuf_dma_sg videobuf_core videodev v4l1_compat ttpci_eeprom
lirc_serial lirc_dev usbhid rtc uhci_hcd 8139too i2c_piix4 i2c_core usbcore evdev
Pid: 4249, comm: modprobe Not tainted (2.6.27-gentoo #3)
EIP: 0060:[<e084d4ef>] EFLAGS: 00010296 CPU: 0
EIP is at i2c_transfer+0x1f/0x80 [i2c_core]
EAX: 00000000 EBX: ffffffa1 ECX: 00000002 EDX: d6c71e3c
ESI: d80cd050 EDI: d8093c00 EBP: d6c71e20 ESP: d6c71e0c
DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
---[ end trace b32d87d0f0db1832 ]---
I added a check for i2c registration success before attaching frontends.
Signed-off-by Matthias Schwarzott <[email protected]>
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cx88-dvb: Fix Oops in case i2c bus failed to register
When enabling extra checks for the i2c-bus of cx88 based cards by loading i2c_algo_bit with bit_test=1 this may trigger an oops when loading cx88_dvb.
This is caused by the extra check code that detects that the sda-line is stuck high and thus does not register the i2c-bus.
cx88-dvb however does not check if the i2c-bus is valid and just uses core->i2c_adap to attach dvb frontend modules. This leads to an oops at the first call to i2c_transfer:
# modprobe i2c_algo_bit bit_test=1
# modprobe cx8802
cx88/2: cx2388x MPEG-TS Driver Manager version 0.0.6 loaded
cx88[0]: quirk: PCIPCI_NATOMA -- set TBFX
cx88[0]: subsystem: 0070:9202, board: Hauppauge Nova-S-Plus DVB-S [card=37,autodetected], frontend(s): 1 cx88[0]: TV tuner type 4, Radio tuner type -1
cx88[0]: SDA stuck high!
cx88[0]: i2c register FAILED
input: cx88 IR (Hauppauge Nova-S-Plus as /class/input/input5
cx88[0]/2: cx2388x 8802 Driver Manager
cx88-mpeg driver manager 0000:00:10.2: enabling device (0154 -> 0156)
cx88-mpeg driver manager 0000:00:10.2: PCI INT A -> Link[LNKD] -> GSI 9 (level, low) -> IRQ 9 cx88[0]/2: found at 0000:00:10.2, rev: 5, irq: 9, latency: 64, mmio: 0xfb000000 cx8802_probe() allocating 1 frontend(s)
cx88/2: cx2388x dvb driver version 0.0.6 loaded
cx88/2: registering cx8802 driver, type: dvb access: shared
cx88[0]/2: subsystem: 0070:9202, board: Hauppauge Nova-S-Plus DVB-S [card=37] cx88[0]/2: cx2388x based DVB/ATSC card
BUG: unable to handle kernel NULL pointer dereference at 00000000
IP: [<e084d4ef>] :i2c_core:i2c_transfer+0x1f/0x80
*pde = 00000000
Modules linked in: cx88_dvb(+) cx8802 cx88xx ir_common i2c_algo_bit tveeprom videobuf_dvb btcx_risc
mga drm ipv6 fscpos eeprom nfsd exportfs stv0299 b2c2_flexcop_pci b2c2_flexcop cx24123 s5h1420 ves1x93 dvb_ttpci dvb_core saa7146_vv saa7146 videobuf_dma_sg videobuf_core videodev v4l1_compat ttpci_eeprom lirc_serial lirc_dev usbhid rtc uhci_hcd 8139too i2c_piix4 i2c_core usbcore evdev
Pid: 4249, comm: modprobe Not tainted (2.6.27-gentoo #3)
EIP: 0060:[<e084d4ef>] EFLAGS: 00010296 CPU: 0
EIP is at i2c_transfer+0x1f/0x80 [i2c_core]
EAX: 00000000 EBX: ffffffa1 ECX: 00000002 EDX: d6c71e3c
ESI: d80cd050 EDI: d8093c00 EBP: d6c71e20 ESP: d6c71e0c
DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
---[ end trace b32d87d0f0db1832 ]---
I added a check for i2c registration success before attaching frontends.
Signed-off-by Matthias Schwarzott <[email protected]>
Index: v4l-dvb/linux/drivers/media/video/cx88/cx88-dvb.c
===================================================================
linux/drivers/media/video/cx88/cx88-dvb.c +5 -1
@@ -605,6 +605,11 @@ static int dvb_register(struct cx8802_de
 	struct videobuf_dvb_frontend *fe0, *fe1 = NULL;
 	int mfe_shared = 0; /* bus not shared by default */
 
+	if (0 != core->i2c_rc) {
+		printk(KERN_ERR "%s/2: no i2c-bus available, cannot attach dvb drivers\n", core->name);
+		goto frontend_detach;
+	}
+
 	/* Get the first frontend */
 	fe0 = videobuf_dvb_get_frontend(&dev->frontends, 1);
 	if (!fe0)
 
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Quoted 7 lines

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{:)==={ Darron Broad <[email protected]>
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