From: Emil Velikov <emil.velikov@xxxxxxxxxxxxx> Parsing config sysfs file wakes up the device. The latter of which may be slow and isn't required to begin with. Reading through config is/was required since the revision is not available by other means, although with a kernel patch in the way that is about to change. Since returning 0 when one might expect a valid value is a no-go add a workaround drmDeviceUseRevisionFile() which one can use to say "I don't care if the revision file returns 0." v2: Complete rework - add new API to control the method, instead of changing it underneat the users' feet. Cc: Michel Dänzer <michel.daenzer@xxxxxxx> Cc: Mauro Santos <registo.mailling@xxxxxxxxx> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98502 Signed-off-by: Emil Velikov <emil.velikov@xxxxxxxxxxxxx> --- I don't have a strong preference for/against this or v1. With this Mesa will require a 2 line patch. With v1 things will get fixed magically, when rebuilt against newer libdrm. Mauro I'll send the mesa patch in a second. Feel free to give it a spin. Thanks --- xf86drm.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--- xf86drm.h | 11 ++++++++++ 2 files changed, 78 insertions(+), 3 deletions(-) diff --git a/xf86drm.c b/xf86drm.c index 52add5e..676effc 100644 --- a/xf86drm.c +++ b/xf86drm.c @@ -113,6 +113,13 @@ void drmSetServerInfo(drmServerInfoPtr info) drm_server_info = info; } +static bool use_revision_file; + +void drmDeviceUseRevisionFile(void) +{ + use_revision_file = true; +} + /** * Output a message to stderr. * @@ -2946,10 +2953,56 @@ static int drmGetMaxNodeName(void) 3 /* length of the node number */; } -static int drmParsePciDeviceInfo(const char *d_name, - drmPciDeviceInfoPtr device) -{ #ifdef __linux__ +static int parse_separate_sysfs_files(const char *d_name, + drmPciDeviceInfoPtr device) +{ +#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0])) + static const char *attrs[] = { + "revision", /* XXX: make sure it's always first, see note below */ + "vendor", + "device", + "subsystem_vendor", + "subsystem_device", + }; + char path[PATH_MAX + 1]; + unsigned int data[ARRAY_SIZE(attrs)]; + FILE *fp; + int ret; + + for (unsigned i = 0; i < ARRAY_SIZE(attrs); i++) { + snprintf(path, PATH_MAX, "/sys/class/drm/%s/device/%s", + d_name, attrs[i]); + fp = fopen(path, "r"); + if (!fp) { + /* Note: First we check the revision, since older kernels + * may not have it. Default to zero in such cases. */ + if (i == 0) { + data[i] = 0; + continue; + } + return -errno; + } + + ret = fscanf(fp, "%x", &data[i]); + fclose(fp); + if (ret != 1) + return -errno; + + } + + device->revision_id = data[0] & 0xff; + device->vendor_id = data[1] & 0xffff; + device->device_id = data[2] & 0xffff; + device->subvendor_id = data[3] & 0xffff; + device->subdevice_id = data[4] & 0xffff; + + return 0; +} + +static int parse_config_sysfs_file(const char *d_name, + drmPciDeviceInfoPtr device) +{ char path[PATH_MAX + 1]; unsigned char config[64]; int fd, ret; @@ -2971,6 +3024,17 @@ static int drmParsePciDeviceInfo(const char *d_name, device->subdevice_id = config[46] | (config[47] << 8); return 0; +} +#endif + +static int drmParsePciDeviceInfo(const char *d_name, + drmPciDeviceInfoPtr device) +{ +#ifdef __linux__ + if (use_revision_file) + return parse_separate_sysfs_files(d_name, device); + + return parse_config_sysfs_file(d_name, device); #else #warning "Missing implementation of drmParsePciDeviceInfo" return -EINVAL; diff --git a/xf86drm.h b/xf86drm.h index 481d882..d1ebc32 100644 --- a/xf86drm.h +++ b/xf86drm.h @@ -796,6 +796,17 @@ extern void drmFreeDevice(drmDevicePtr *device); extern int drmGetDevices(drmDevicePtr devices[], int max_devices); extern void drmFreeDevices(drmDevicePtr devices[], int count); + +/** + * Force any sequential calls to drmGetDevice/drmGetDevices to use the + * revision sysfs file instead of config one. The latter wakes up the device + * if powered off. + * + * A value of 0 will be returned for the revision_id field if the sysfs file + * is missing. DO NOT USE THIS if you depend on a correct revision_id. + */ +extern void drmDeviceUseRevisionFile(void); + #if defined(__cplusplus) } #endif -- 2.10.2 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
