From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lyude Subject: [PATCH v6 3/4] drm/dp_helper: Perform throw-away read before actual read in drm_dp_dpcd_read() Date: Fri, 15 Apr 2016 10:25:35 -0400 Message-ID: <1460730335-5012-1-git-send-email-cpaul@redhat.com> References: <20160414170143.GS4329@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20160414170143.GS4329@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= , dri-devel@lists.freedesktop.org Cc: David Airlie , intel-gfx@lists.freedesktop.org, open list List-Id: dri-devel@lists.freedesktop.org VGhpcyBpcyBwYXJ0IG9mIGEgcGF0Y2ggc2VyaWVzIHRvIG1pZ3JhdGUgYWxsIG9mIHRoZSB3b3Jr YXJvdW5kcyBmb3IKY29tbW9ubHkgc2VlbiBiZWhhdmlvciBmcm9tIGJhZCBzaW5rcyBpbiBpbnRl bF9kcF9kcGNkX3JlYWRfd2FrZSgpIHRvIGRybSdzCkRQIGhlbHBlci4KClNvbWUgc2lua3Mgd2ls bCBqdXN0IHJldHVybiBnYXJiYWdlIGZvciB0aGUgZmlyc3QgYXV4IHRyYW5hY3Rpb24gdGhleQpy ZWNlaXZlIHdoZW4gY29taW5nIG91dCBvZiBzbGVlcCBtb2RlLCBzbyB3ZSBuZWVkIHRvIHBlcmZv cm0gYW4gYWRkaXRpb25hbApyZWFkIGJlZm9yZSB0aGUgYWN0dWFsIHJlYWQgdG8gd29ya2Fyb3Vu ZCB0aGlzLgoKCQkJICAgIENoYW5nZXMgc2luY2UgdjUKLSBJZiB0aGUgdGhyb3dhd2F5IHJlYWQg aW4gZHJtX2RwX2RwY2RfcmVhZCgpIGZhaWxzLCByZXR1cm4gdGhlIGVycm9yCiAgZnJvbSB0aGF0 IGluc3RlYWQgb2YgY29udGludWluZy4gVGhpcyBmb2xsb3dzIHRoZSBzYW1lIGxvZ2ljIHdlIGRv IGluCiAgZHJtX2RwX2RwY2RfYWNjZXNzKCkgKGUuZy4gdGhlIGVycm9yIGZyb20gdGhlIGZpcnN0 IHRyYW5zYWN0aW9uIG1heQogIGRpZmZlciBmcm9tIHRoZSBlcnJvcnMgdGhhdCBwcm9jZWVkaW5n IGF0dGVtcHRzIG1pZ2h0IHJldHVybikuCgpTaWduZWQtb2ZmLWJ5OiBMeXVkZSA8Y3BhdWxAcmVk aGF0LmNvbT4KLS0tCiBkcml2ZXJzL2dwdS9kcm0vZHJtX2RwX2hlbHBlci5jIHwgMTkgKysrKysr KysrKysrKysrKysrKwogMSBmaWxlIGNoYW5nZWQsIDE5IGluc2VydGlvbnMoKykKCmRpZmYgLS1n aXQgYS9kcml2ZXJzL2dwdS9kcm0vZHJtX2RwX2hlbHBlci5jIGIvZHJpdmVycy9ncHUvZHJtL2Ry bV9kcF9oZWxwZXIuYwppbmRleCA1NDBjM2U0Li5lZWFmNWE3IDEwMDY0NAotLS0gYS9kcml2ZXJz L2dwdS9kcm0vZHJtX2RwX2hlbHBlci5jCisrKyBiL2RyaXZlcnMvZ3B1L2RybS9kcm1fZHBfaGVs cGVyLmMKQEAgLTI0OCw2ICsyNDgsMjUgQEAgdW5sb2NrOgogc3NpemVfdCBkcm1fZHBfZHBjZF9y ZWFkKHN0cnVjdCBkcm1fZHBfYXV4ICphdXgsIHVuc2lnbmVkIGludCBvZmZzZXQsCiAJCQkgdm9p ZCAqYnVmZmVyLCBzaXplX3Qgc2l6ZSkKIHsKKwlpbnQgcmV0OworCisJLyoKKwkgKiBIUCBaUjI0 dyBjb3JydXB0cyB0aGUgZmlyc3QgRFBDRCBhY2Nlc3MgYWZ0ZXIgZW50ZXJpbmcgcG93ZXIgc2F2 ZQorCSAqIG1vZGUuIEVnLiBvbiBhIHJlYWQsIHRoZSBlbnRpcmUgYnVmZmVyIHdpbGwgYmUgZmls bGVkIHdpdGggdGhlIHNhbWUKKwkgKiBieXRlLiBEbyBhIHRocm93IGF3YXkgcmVhZCB0byBhdm9p ZCBjb3JydXB0aW5nIGFueXRoaW5nIHdlIGNhcmUKKwkgKiBhYm91dC4gQWZ0ZXJ3YXJkcyB0aGlu Z3Mgd2lsbCB3b3JrIGNvcnJlY3RseSB1bnRpbCB0aGUgbW9uaXRvcgorCSAqIGdldHMgd29rZW4g dXAgYW5kIHN1YnNlcXVlbnRseSByZS1lbnRlcnMgcG93ZXIgc2F2ZSBtb2RlLgorCSAqCisJICog VGhlIHVzZXIgcHJlc3NpbmcgYW55IGJ1dHRvbiBvbiB0aGUgbW9uaXRvciBpcyBlbm91Z2ggdG8g d2FrZSBpdAorCSAqIHVwLCBzbyB0aGVyZSBpcyBubyBwYXJ0aWN1bGFybHkgZ29vZCBwbGFjZSB0 byBkbyB0aGUgd29ya2Fyb3VuZC4KKwkgKiBXZSBqdXN0IGhhdmUgdG8gZG8gaXQgYmVmb3JlIGFu eSBEUENEIGFjY2VzcyBhbmQgaG9wZSB0aGF0IHRoZQorCSAqIG1vbml0b3IgZG9lc24ndCBwb3dl ciBkb3duIGV4YWN0bHkgYWZ0ZXIgdGhlIHRocm93IGF3YXkgcmVhZC4KKwkgKi8KKwlyZXQgPSBk cm1fZHBfZHBjZF9hY2Nlc3MoYXV4LCBEUF9BVVhfTkFUSVZFX1JFQUQsIERQX0RQQ0RfUkVWLCBi dWZmZXIsCisJCQkJIDEpOworCWlmIChyZXQgIT0gMSkKKwkJcmV0dXJuIHJldDsKKwogCXJldHVy biBkcm1fZHBfZHBjZF9hY2Nlc3MoYXV4LCBEUF9BVVhfTkFUSVZFX1JFQUQsIG9mZnNldCwgYnVm ZmVyLAogCQkJCSAgc2l6ZSk7CiB9Ci0tIAoyLjUuNQoKX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX18KSW50ZWwtZ2Z4IG1haWxpbmcgbGlzdApJbnRlbC1nZnhA bGlzdHMuZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxt YW4vbGlzdGluZm8vaW50ZWwtZ2Z4Cg==