Do not unconditionally invoke function 0x1B without checking for its availability, it leads to an infinite loop on some firmware.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=104791 Fixes: 5addcf0a5f0fad ("nouveau: add runtime PM support (v0.9)") Signed-off-by: Peter Wu peter@lekensteyn.nl --- v2: only write optimus_funcs when an Optimus DSM is found. --- drivers/gpu/drm/nouveau/nouveau_acpi.c | 43 ++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c index cdf5227..009712a 100644 --- a/drivers/gpu/drm/nouveau/nouveau_acpi.c +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c @@ -45,6 +45,7 @@ static struct nouveau_dsm_priv { bool dsm_detected; bool optimus_detected; + bool flags_func_detected; acpi_handle dhandle; acpi_handle rom_handle; } nouveau_dsm_priv; @@ -58,7 +59,6 @@ bool nouveau_is_v1_dsm(void) { }

#define NOUVEAU_DSM_HAS_MUX 0x1 -#define NOUVEAU_DSM_HAS_OPT 0x2

#ifdef CONFIG_VGA_SWITCHEROO static const char nouveau_dsm_muid[] = { @@ -110,9 +110,9 @@ static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t * * requirements on the fourth parameter, so a private implementation * instead of using acpi_check_dsm(). */ -static int nouveau_check_optimus_dsm(acpi_handle handle) +static uint32_t nouveau_check_optimus_dsm(acpi_handle handle) { - int result; + uint32_t result;

/* * Function 0 returns a Buffer containing available functions. @@ -123,9 +123,13 @@ static int nouveau_check_optimus_dsm(acpi_handle handle)

/* * ACPI Spec v4 9.14.1: if bit 0 is zero, no function is supported. - * If the n-th bit is enabled, function n is supported + * If the n-th bit is enabled, function n is supported. + * Check for both bit zero and the NOUVEAU_DSM_OPTIMUS_CAPS since + * some implementations return 0x80000001 on invalid parameters. */ - return result & 1 && result & (1 << NOUVEAU_DSM_OPTIMUS_CAPS); + if (result & 1 && result & (1 << NOUVEAU_DSM_OPTIMUS_CAPS)) + return result; + return 0; }

static int nouveau_dsm(acpi_handle handle, int func, int arg) @@ -212,10 +216,11 @@ static const struct vga_switcheroo_handler nouveau_dsm_handler = { .get_client_id = nouveau_dsm_get_client_id, };

-static int nouveau_dsm_pci_probe(struct pci_dev *pdev) +static int nouveau_dsm_pci_probe(struct pci_dev *pdev, uint32_t *optimus_funcs) { acpi_handle dhandle; int retval = 0; + uint32_t supported_funcs;

dhandle = ACPI_HANDLE(&pdev->dev); if (!dhandle) @@ -228,11 +233,10 @@ static int nouveau_dsm_pci_probe(struct pci_dev *pdev) 1 << NOUVEAU_DSM_POWER)) retval |= NOUVEAU_DSM_HAS_MUX;

- if (nouveau_check_optimus_dsm(dhandle)) - retval |= NOUVEAU_DSM_HAS_OPT; - - if (retval & NOUVEAU_DSM_HAS_OPT) { + supported_funcs = nouveau_check_optimus_dsm(dhandle); + if (supported_funcs) { uint32_t result; + *optimus_funcs = supported_funcs; nouveau_optimus_dsm(dhandle, NOUVEAU_DSM_OPTIMUS_CAPS, 0, &result); dev_info(&pdev->dev, "optimus capabilities: %s, status %s%s\n", @@ -252,7 +256,7 @@ static bool nouveau_dsm_detect(void) struct acpi_buffer buffer = {sizeof(acpi_method_name), acpi_method_name}; struct pci_dev *pdev = NULL; int has_dsm = 0; - int has_optimus = 0; + uint32_t optimus_funcs = 0; int vga_count = 0; bool guid_valid; int retval; @@ -268,30 +272,28 @@ static bool nouveau_dsm_detect(void) while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) { vga_count++;

- retval = nouveau_dsm_pci_probe(pdev); + retval = nouveau_dsm_pci_probe(pdev, &optimus_funcs); if (retval & NOUVEAU_DSM_HAS_MUX) has_dsm |= 1; - if (retval & NOUVEAU_DSM_HAS_OPT) - has_optimus = 1; }

while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_3D << 8, pdev)) != NULL) { vga_count++;

- retval = nouveau_dsm_pci_probe(pdev); + retval = nouveau_dsm_pci_probe(pdev, &optimus_funcs); if (retval & NOUVEAU_DSM_HAS_MUX) has_dsm |= 1; - if (retval & NOUVEAU_DSM_HAS_OPT) - has_optimus = 1; }

/* find the optimus DSM or the old v1 DSM */ - if (has_optimus == 1) { + if (optimus_funcs) { acpi_get_name(nouveau_dsm_priv.dhandle, ACPI_FULL_PATHNAME, &buffer); printk(KERN_INFO "VGA switcheroo: detected Optimus DSM method %s handle\n", acpi_method_name); nouveau_dsm_priv.optimus_detected = true; + nouveau_dsm_priv.flags_func_detected = + optimus_funcs & (1 << NOUVEAU_DSM_OPTIMUS_FLAGS); ret = true; } else if (vga_count == 2 && has_dsm && guid_valid) { acpi_get_name(nouveau_dsm_priv.dhandle, ACPI_FULL_PATHNAME, @@ -324,8 +326,9 @@ void nouveau_switcheroo_optimus_dsm(void) if (!nouveau_dsm_priv.optimus_detected) return;

- nouveau_optimus_dsm(nouveau_dsm_priv.dhandle, NOUVEAU_DSM_OPTIMUS_FLAGS, - 0x3, &result); + if (nouveau_dsm_priv.flags_func_detected) + nouveau_optimus_dsm(nouveau_dsm_priv.dhandle, + NOUVEAU_DSM_OPTIMUS_FLAGS, 0x3, &result);

nouveau_optimus_dsm(nouveau_dsm_priv.dhandle, NOUVEAU_DSM_OPTIMUS_CAPS, NOUVEAU_DSM_OPTIMUS_SET_POWERDOWN, &result);