Messages in this thread | | | Date | Sun, 18 Jun 2023 15:08:03 +0200 | Subject | Re: [PATCH 1/2] i2c: i801: Force no IRQ for Dell Latitude E7450 | From | Marius Hoch <> |
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Hi Jean,
On 04/06/2023 16:38, Jean Delvare wrote: > On Sun, 14 May 2023 12:36:33 +0200, Marius Hoch wrote: >> The Dell Latitude E7450 uses IRQ 18 for the accelerometer, >> but also claims that the SMBus uses IRQ 18. This will >> result in: >> >> i801_smbus 0000:00:1f.3: PCI INT C: failed to register GSI >> i801_smbus 0000:00:1f.3: Failed to enable SMBus PCI device (-16) >> i801_smbus: probe of 0000:00:1f.3 failed with error -16 >> >> Force the SMBus IRQ to IRQ_NOTCONNECTED in this case, so that >> we fall back to polling, which also seems to be what the (very >> dated) Windows 7 drivers on the Dell Latitude E7450 do. >> >> This was tested on Dell Latitude E7450. >> >> Signed-off-by: Marius Hoch <mail@mariushoch.de> >> --- >> drivers/i2c/busses/i2c-i801.c | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c >> index ac5326747c51..5fd2ac585160 100644 >> --- a/drivers/i2c/busses/i2c-i801.c >> +++ b/drivers/i2c/busses/i2c-i801.c >> @@ -1624,6 +1624,20 @@ static void i801_setup_hstcfg(struct i801_priv *priv) >> pci_write_config_byte(priv->pci_dev, SMBHSTCFG, hstcfg); >> } >> >> +/** > As reported by the kernel test robot, please don't start a comment with > /** unless it's a kernel-doc-style comment. > >> + * These DELL devices claim an IRQ for the SMBus (usually 18), but we can't use >> + * it, as its actually for the I2C accelerometer. >> + */ >> +static const struct dmi_system_id dmi_force_no_irq[] = { >> + { >> + .matches = { >> + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), >> + DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E7450"), >> + }, >> + }, >> + {} /* Terminating entry */ >> +}; >> + >> static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) >> { >> int err, i; >> @@ -1657,6 +1671,12 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) >> if (!(priv->features & FEATURE_BLOCK_BUFFER)) >> priv->features &= ~FEATURE_BLOCK_PROC; >> >> + if (dmi_check_system(dmi_force_no_irq)) { > If the problem is caused by dev->irq being 255, and now that we know > that this value is special on x86, wouldn't it make more sense to > restrict this quirk to CONFIG_X86 and simply check for dev->irq == > 0xff? This would save us the extra effort of maintaining a list of > machines which need the quirk. > >> + /* Force no IRQ for these devices, otherwise pcim_enable_device will fail */ >> + dev->irq = IRQ_NOTCONNECTED; >> + dev->irq_managed = 1; > This field is undocumented so I have no idea what it does. Is it not > sufficient to set irq to IRQ_NOTCONNECTED? If irq_managed is not set our irq value will be entirely ignored it seems (thus leading to the same code path/ failure initially outlined). > >> + } >> + >> err = pcim_enable_device(dev); >> if (err) { >> dev_err(&dev->dev, "Failed to enable SMBus PCI device (%d)\n", >
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