From: Daniel Scheller <>

It is known that MSI interrupts - while working quite well so far - can
still cause issues on some hardware platforms (causing I2C timeouts due
to unhandled interrupts). The msi variable/option is set to 1 by default.
So, add a Kconfig option prefixed with "EXPERIMENTAL" that will control
the default value of that modparam, defaulting to off for a better
user experience and (guaranteed) stable operation "per default".

Cc: Ralph Metzler <>
Signed-off-by: Daniel Scheller <>
Tested-by: Richard Scobie <>
Tested-by: Jasmin Jessich <>
Tested-by: Dietmar Spingler <>
Tested-by: Manfred Knick <>
 drivers/media/pci/ddbridge/Kconfig         | 15 +++++++++++++++
 drivers/media/pci/ddbridge/ddbridge-main.c | 11 +++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/media/pci/ddbridge/Kconfig 
index c79a58fa5fc3..1330b2ecc72a 100644
--- a/drivers/media/pci/ddbridge/Kconfig
+++ b/drivers/media/pci/ddbridge/Kconfig
@@ -26,3 +26,18 @@ config DVB_DDBRIDGE
          - CineS2 V7/V7A and DuoFlex S2 V4 (ST STV0910-based)
          Say Y if you own such a card and want to use it.
+       bool "Enable Message Signaled Interrupts (MSI) per default 
+       depends on DVB_DDBRIDGE
+       depends on PCI_MSI
+       default n
+       ---help---
+         Use PCI MSI (Message Signaled Interrupts) per default. Enabling this
+         might lead to I2C errors originating from the bridge in conjunction
+         with certain SATA controllers, requiring a reload of the ddbridge
+         module. MSI can still be disabled by passing msi=0 as option, as
+         this will just change the msi option default value.
+         If you're unsure, concerned about stability and don't want to pass
+         module options in case of troubles, say N.
diff --git a/drivers/media/pci/ddbridge/ddbridge-main.c 
index 5094d2ef79d6..5a930a6e9fb2 100644
--- a/drivers/media/pci/ddbridge/ddbridge-main.c
+++ b/drivers/media/pci/ddbridge/ddbridge-main.c
@@ -47,10 +47,17 @@ MODULE_PARM_DESC(adapter_alloc,
                 "0-one adapter per io, 1-one per tab with io, 2-one per tab, 
3-one for all");
 int msi = 1;
+int msi;
 module_param(msi, int, 0444);
-                " Control MSI interrupts: 0-disable, 1-enable (default)");
+MODULE_PARM_DESC(msi, "Control MSI interrupts: 0-disable, 1-enable (default)");
+MODULE_PARM_DESC(msi, "Control MSI interrupts: 0-disable (default), 1-enable");
 int ci_bitrate = 70000;

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