On Thu, Dec 29, 2022 at 11:12:30AM -0500, Rodrigo Vivi wrote:
> There are new cases where we want to block i915 probe, such
> as when experimenting or developing the new Xe driver.
>
> But also, with the new hibrid cards, users or developers might
> want to use i915 only on integrated and fully block the probe
> of the i915 for the discrete. Or vice versa.
>
> Oh, and there are even older development and validation reasons,
> like when you use some distro where the modprobe.blacklist is
> not present.
>
> But in any case, let's introduce a more granular control, but without
> introducing yet another parameter, but using the existent force_probe
> one.
>
> Just by adding a ! in the begin of the id in the force_probe, like
> in this case where we would block the probe for Alder Lake:
>
> $ insmod i915.ko force_probe='!46a6'
>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/Kconfig | 13 ++++++++++---
> drivers/gpu/drm/i915/i915_params.c | 2 +-
> drivers/gpu/drm/i915/i915_pci.c | 29 +++++++++++++++++++++++++----
> 3 files changed, 36 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
> index 3efce05d7b57..8873cd0355b7 100644
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -54,24 +54,31 @@ config DRM_I915
> If "M" is selected, the module will be called i915.
>
> config DRM_I915_FORCE_PROBE
> - string "Force probe driver for selected new Intel hardware"
> + string "Force probe i915 for selected Intel hardware IDs"
> depends on DRM_I915
> help
> This is the default value for the i915.force_probe module
> parameter. Using the module parameter overrides this option.
>
> - Force probe the driver for new Intel graphics devices that are
> + Force probe the i915 for Intel graphics devices that are
> recognized but not properly supported by this kernel version. It is
> recommended to upgrade to a kernel version with proper support as soon
> as it is available.
>
> + It can also be used to block the probe of recognized and fully
> + supported devices.
> +
> Use "" to disable force probe. If in doubt, use this.
>
> - Use "<pci-id>[,<pci-id>,...]" to force probe the driver for listed
> + Use "<pci-id>[,<pci-id>,...]" to force probe the i915 for listed
> devices. For example, "4500" or "4500,4571".
>
> Use "*" to force probe the driver for all known devices.
>
> + Use "!" right before the ID to block the probe of the device. For
> + example, "4500,!4571" forces the probe of 4500 and blocks the probe of
> + 4571.
> +
> config DRM_I915_CAPTURE_ERROR
> bool "Enable capturing GPU state following a hang"
> depends on DRM_I915
> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
> index 61578f2860cd..d634bd3f641a 100644
> --- a/drivers/gpu/drm/i915/i915_params.c
> +++ b/drivers/gpu/drm/i915/i915_params.c
> @@ -122,7 +122,7 @@ i915_param_named_unsafe(enable_psr2_sel_fetch, bool, 0400,
> "Default: 0");
>
> i915_param_named_unsafe(force_probe, charp, 0400,
> - "Force probe the driver for specified devices. "
> + "Force probe options for specified supported devices. "
> "See CONFIG_DRM_I915_FORCE_PROBE for details.");
>
> i915_param_named_unsafe(disable_power_well, int, 0400,
> diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
> index 668e9da52584..fc1383f3a646 100644
> --- a/drivers/gpu/drm/i915/i915_pci.c
> +++ b/drivers/gpu/drm/i915/i915_pci.c
> @@ -1253,7 +1253,7 @@ static void i915_pci_remove(struct pci_dev *pdev)
> }
>
> /* is device_id present in comma separated list of ids */
> -static bool force_probe(u16 device_id, const char *devices)
> +static bool device_id_in_list(u16 device_id, const char *devices, bool negative)
> {
> char *s, *p, *tok;
> bool ret;
> @@ -1272,6 +1272,12 @@ static bool force_probe(u16 device_id, const char *devices)
> for (p = s, ret = false; (tok = strsep(&p, ",")) != NULL; ) {
> u16 val;
>
> + if (negative && tok[0] == '!')
> + tok++;
> + else if ((negative && tok[0] != '!') ||
> + (!negative && tok[0] == '!'))
> + continue;
> +
> if (kstrtou16(tok, 16, &val) == 0 && val == device_id) {
> ret = true;
> break;
> @@ -1283,6 +1289,16 @@ static bool force_probe(u16 device_id, const char *devices)
> return ret;
> }
>
> +static bool id_forced(u16 device_id)
> +{
> + return device_id_in_list(device_id, i915_modparams.force_probe, false);
> +}
> +
> +static bool id_blocked(u16 device_id)
> +{
> + return device_id_in_list(device_id, i915_modparams.force_probe, true);
> +}
I think id_blocked() would return true for any device id if force_probe was "*".
> +
> bool i915_pci_resource_valid(struct pci_dev *pdev, int bar)
> {
> if (!pci_resource_flags(pdev, bar))
> @@ -1308,10 +1324,9 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> (struct intel_device_info *) ent->driver_data;
> int err;
>
> - if (intel_info->require_force_probe &&
> - !force_probe(pdev->device, i915_modparams.force_probe)) {
> + if (intel_info->require_force_probe && !id_forced(pdev->device)) {
> dev_info(&pdev->dev,
> - "Your graphics device %04x is not properly supported by the driver in this\n"
> + "Your graphics device %04x is not properly supported by i915 in this\n"
> "kernel version. To force driver probe anyway, use i915.force_probe=%04x\n"
> "module parameter or CONFIG_DRM_I915_FORCE_PROBE=%04x configuration option,\n"
> "or (recommended) check for kernel updates.\n",
> @@ -1319,6 +1334,12 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> return -ENODEV;
> }
>
> + if (id_blocked(pdev->device)) {
> + dev_info(&pdev->dev, "I915 probe blocked for Device ID %04x.\n",
> + pdev->device);
> + return -ENODEV;
> + }
> +
> /* Only bind to function 0 of the device. Early generations
> * used function 1 as a placeholder for multi-head. This causes
> * us confusion instead, especially on the systems where both
> --
> 2.38.1
>
